Upgrade ci postgreSQL version from 9.5 to 10 (#76)

* add postgres 10.21, 11.16, 12.11, 13.7, 14.3
* use versions existing on hub.docker.com (10.20, 11.15, 12.10, 13.6, 14.2)
* Upgrade ci postgres version from 9.5 to 10 (drop 10.20, 11.15, 12.10, 13.6, 14.2)

Co-authored-by: Ko Nagase <[email protected]>

Author: matobaa

.github/workflows/test.yml

@@ -42,7 +42,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby: [2.5, 2.6, 2.7]
-        db_version: [9.5]
+        db_version: [10]
     runs-on: ubuntu-latest
     container:
       image: ruby:${{ matrix.ruby }}