Set GDB version number to 13.2.

This commit changes gdb/version.in to 13.2.
diff --git a/gdb/version.in b/gdb/version.in
index 112f9dd..5ba096e 100644
--- a/gdb/version.in
+++ b/gdb/version.in
@@ -1 +1 @@
-13.1.90.DATE-git
+13.2