debian/rules: Use execute_before_dh_auto_install.

Otherwise pg_buildext doesn't get called and the build picks up the wrong
pg_config.

debian/changelog

+postgresql-q3c (2.0.1-3) unstable; urgency=medium
+
+  * debian/rules: Use execute_before_dh_auto_install.
+
+ -- Christoph Berg <myon@debian.org>  Wed, 07 Aug 2024 16:30:03 +0200
+
 postgresql-q3c (2.0.1-2) unstable; urgency=medium
 
   * Install docs to non-generic name (Closes: #1073800)

debian/rules

@@ -6,6 +6,6 @@ override_dh_pgxs_test:
 %:
 	dh $@ --with pgxs_loop
 
-override_dh_auto_install:
+# pgxs_loop overrides dh_auto_install internally, use execute_before_ here, not override_dh_auto_install
+execute_before_dh_auto_install:
 	cp README.md q3c.md
-	dh_auto_install