Set GDB version number to 16.2.

This commit changes gdb/version.in to 16.2.
diff --git a/gdb/version.in b/gdb/version.in
index 437e7be..f6eb05e 100644
--- a/gdb/version.in
+++ b/gdb/version.in
@@ -1 +1 @@
-16.1.90.DATE-git
+16.2