Set PostgreSQL 12 as the minimum supported version

Changelog: changed

doc/install/requirements.md

@@ -116,6 +116,7 @@ the following table) as these were used for development and testing:
 |----------------|----------------------------|
 | 10.0           | 9.6                        |
 | 13.0           | 11                         |
+| 14.0           | 12                         |
 
 You must also ensure the following extensions are loaded into every
 GitLab database. [Read more about this requirement, and troubleshooting](postgresql_extensions.md).

lib/gitlab/database.rb

@@ -14,7 +14,7 @@ module Database
 
     # Minimum PostgreSQL version requirement per documentation:
     # https://docs.gitlab.com/ee/install/requirements.html#postgresql-requirements
-    MINIMUM_POSTGRES_VERSION = 11
+    MINIMUM_POSTGRES_VERSION = 12
 
     # https://www.postgresql.org/docs/9.2/static/datatype-numeric.html
     MAX_INT_VALUE = 2147483647

spec/lib/gitlab/database_spec.rb

@@ -125,10 +125,10 @@
       expect(described_class.postgresql_minimum_supported_version?).to eq(false)
     end
 
-    it 'returns true when using PostgreSQL 11' do
+    it 'returns false when using PostgreSQL 11' do
       allow(described_class).to receive(:version).and_return('11')
 
-      expect(described_class.postgresql_minimum_supported_version?).to eq(true)
+      expect(described_class.postgresql_minimum_supported_version?).to eq(false)
     end
 
     it 'returns true when using PostgreSQL 12' do