(maint) Merge up b7cb119 to main

Merge conflicts around the ubuntu 18.08 -> latest
Generated by me

* 6.x:
  (packaging) Updating manpage file for 6.x
  (PUP-11626) Update Ubuntu GitHub Action runners

Author: cthorn42

.github/workflows/checks.yaml

@@ -16,9 +16,9 @@ jobs:
     strategy:
       matrix:
         cfg:
-          - {check: rubocop,  os: ubuntu-18.04, ruby: '2.5'}
-          - {check: commits,  os: ubuntu-18.04, ruby: '2.5'}
-          - {check: warnings, os: ubuntu-18.04, ruby: '2.5'}
+          - {check: rubocop, os: ubuntu-latest, ruby: 2.5}
+          - {check: commits, os: ubuntu-latest, ruby: 2.5}
+          - {check: warnings, os: ubuntu-latest, ruby: 2.5}
 
     runs-on: ${{ matrix.cfg.os }}
     steps:

.github/workflows/rspec_tests.yaml

@@ -16,11 +16,11 @@ jobs:
     strategy:
       matrix:
         cfg:
-          - {os: ubuntu-18.04, ruby: '2.5'}
-          - {os: ubuntu-18.04, ruby: '2.6'}
-          - {os: ubuntu-18.04, ruby: '2.7'}
-          - {os: ubuntu-18.04, ruby: '3.0'}
-          - {os: ubuntu-18.04, ruby: 'jruby-9.2.17.0'}
+          - {os: ubuntu-latest, ruby: '2.5'}
+          - {os: ubuntu-latest, ruby: '2.6'}
+          - {os: ubuntu-latest, ruby: '2.7'}
+          - {os: ubuntu-latest, ruby: '3.0'}
+          - {os: ubuntu-latest, ruby: 'jruby-9.2.17.0'}
           - {os: windows-2019, ruby: '2.5'}
           - {os: windows-2019, ruby: '2.6'}
           - {os: windows-2019, ruby: '2.7'}