Update GitHub actions/checkout from v2 to v3

https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/

Signed-off-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>

.github/workflows/installcheck.yml

@@ -48,7 +48,7 @@ jobs:
           /tmp/pgsql/bin/pg_ctl -D /tmp/data -l /tmp/data/postgresql.log start
 
       - name: Checkout pg_toolkit_brazil extension repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
         with:
           fetch-depth: 2