Adjust locations which have an incorrect copyright year

A few patches committed after ca3b3748 mistakenly forgot to make the
copyright year 2021.  Fix these.

Discussion: https://postgr.es/m/CAApHDvqyLmd9P2oBQYJ=DbrV8QwyPRdmXtCTFYPE08h+ip0UJw@mail.gmail.com

contrib/pageinspect/gistfuncs.c

@@ -2,7 +2,7 @@
  * gistfuncs.c
  *		Functions to investigate the content of GiST indexes
  *
- * Copyright (c) 2014-2020, PostgreSQL Global Development Group
+ * Copyright (c) 2014-2021, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
  *		contrib/pageinspect/gistfuncs.c

src/backend/access/brin/brin_bloom.c

@@ -2,7 +2,7 @@
  * brin_bloom.c
  *		Implementation of Bloom opclass for BRIN
  *
- * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/backend/access/brin/brin_minmax_multi.c

@@ -2,7 +2,7 @@
  * brin_minmax_multi.c
  *		Implementation of Multi Min/Max opclass for BRIN
  *
- * Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/backend/rewrite/rewriteSearchCycle.c

@@ -3,7 +3,7 @@
  * rewriteSearchCycle.c
  *		Support for rewriting SEARCH and CYCLE clauses.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/backend/utils/adt/jsonbsubs.c

@@ -3,7 +3,7 @@
  * jsonbsubs.c
  *	  Subscripting support functions for jsonb.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  *

src/common/hex.c

@@ -3,7 +3,7 @@
  * hex.c
  *	  Encoding and decoding routines for hex.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/common/hmac.c

@@ -5,7 +5,7 @@
  *
  * Fallback implementation of HMAC, as specified in RFC 2104.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/common/hmac_openssl.c

@@ -5,7 +5,7 @@
  *
  * This should only be used if code is compiled with OpenSSL support.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/common/sha1.c

@@ -5,7 +5,7 @@
  *
  * Fallback implementation of SHA1, as specified in RFC 3174.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/common/sha1_int.h

@@ -3,7 +3,7 @@
  * sha1_int.h
  *	  Internal headers for fallback implementation of SHA1
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/include/common/hex.h

@@ -3,7 +3,7 @@
  *	hex.h
  *	  Encoding and decoding routines for hex strings.
  *
- *	Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ *	Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  *	Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/include/common/hmac.h

@@ -3,7 +3,7 @@
  * hmac.h
  *	  Generic headers for HMAC
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION

src/include/common/sha1.h

@@ -3,7 +3,7 @@
  * sha1.h
  *	  Constants related to SHA1.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * src/include/common/sha1.h

src/include/port/pg_iovec.h

@@ -3,7 +3,7 @@
  * pg_iovec.h
  *	  Header for vectored I/O functions, to use in place of <sys/uio.h>.
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * src/include/port/pg_iovec.h

src/include/rewrite/rewriteSearchCycle.h

@@ -4,7 +4,7 @@
  *		Support for rewriting SEARCH and CYCLE clauses.
  *
  *
- * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * src/include/rewrite/rewriteSearchCycle.h