Fix bison warning

src/parser.y:63.1-25: warning: deprecated directive, use '%define api.prefix {plproxy_yy}' [-Wdeprecated]
   63 | %name-prefix="plproxy_yy"
      | ^~~~~~~~~~~~~~~~~~~~~~~~~

databases/postgresql-plproxy/files/patch-src-parser.y

@@ -0,0 +1,11 @@
+--- src/parser.y.orig	2017-10-08 08:53:35 UTC
++++ src/parser.y
+@@ -60,7 +60,7 @@ static void reset_parser_vars(void)
+  * same range of Bison versions that are supported also
+  * by PostgreSQL.
+  */
+-%name-prefix="plproxy_yy"
++%define api.prefix {plproxy_yy}
+ 
+ %token <str> CONNECT CLUSTER RUN ON ALL ANY SELECT
+ %token <str> IDENT NUMBER FNCALL SPLIT STRING