Update copyright for 2021

Backpatch-through: 9.5

src/backend/optimizer/plan/analyzejoins.c

@@ -11,7 +11,7 @@
  * is that we have to work harder to clean up after ourselves when we modify
  * the query, since the derived data structures have to be updated too.
  *
- * 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/backend/optimizer/plan/createplan.c

@@ -5,7 +5,7 @@
  *	  Planning is complete, we just need to convert the selected
  *	  Path into a Plan.
  *
- * 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/backend/optimizer/plan/initsplan.c

@@ -3,7 +3,7 @@
  * initsplan.c
  *	  Target list, qualification, joininfo initialization routines
  *
- * 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/backend/optimizer/plan/planagg.c

@@ -17,7 +17,7 @@
  * scan all the rows anyway.
  *
  *
- * 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/backend/optimizer/plan/planmain.c

@@ -9,7 +9,7 @@
  * shorn of features like subselects, inheritance, aggregates, grouping,
  * and so on.  (Those are the things planner.c deals with.)
  *
- * 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/backend/optimizer/plan/planner.c

@@ -3,7 +3,7 @@
  * planner.c
  *	  The query optimizer external interface.
  *
- * 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/backend/optimizer/plan/setrefs.c

@@ -4,7 +4,7 @@
  *	  Post-processing of a completed plan tree: fix references to subplan
  *	  vars, compute regproc values for operators, etc
  *
- * 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/backend/optimizer/plan/subselect.c

@@ -6,7 +6,7 @@
  * This module deals with SubLinks and CTEs, but not subquery RTEs (i.e.,
  * not sub-SELECT-in-FROM cases).
  *
- * 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