Remove Common, Rework External Chat Support, & Bugfixes (!5)

Co-authored-by: Layla <layla@layla.gg>
Reviewed-on: https://gitea.sumulayla.synology.me/layla/birdbot/pulls/5

.github/workflows/publish_release.yaml

@@ -20,7 +20,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '>=1.19.0'
+          go-version: '1.20'
       - name: Version
         run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
       - name: Test

.github/workflows/validate.yaml

@@ -14,7 +14,7 @@ jobs:
       - name: Setup Go
         uses: actions/setup-go@v3
         with:
-          go-version: '>=1.19.0'
+          go-version: '1.20'
       - name: Test
         run: |
           make test