Created Actions workflow for nvim container build. (#3)

Co-authored-by: Shaun Setlock <shaun@setlock.net>
Reviewed-on: https://www.gitea.setlock.net/shaun/dotfiles/pulls/3

.gitea/workflows/neovim_container_docker_build.yml

@@ -0,0 +1,47 @@
+# .gitea/workflows/docker-build-push.yml
+name: Build and Push Docker Image
+
+on:
+  push:
+    branches:
+      - main
+      - master
+    tags:
+      - "v*" # triggers when you push a tag like v1.0.0
+    paths:
+      - "**/Dockerfile"
+
+  workflow_dispatch: # manual run button
+
+jobs:
+  build-and-push:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to Gitea Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: gitea.example.com
+          username: ${{ secrets.GITEA_USERNAME }}
+          password: ${{ secrets.GITEA_TOKEN }}
+
+      - name: Extract Tag Name (if any)
+        id: get_tag
+        run: |
+          echo "GIT_TAG=${GITHUB_REF##*/}" >> $GITHUB_ENV
+
+      - name: Build and Push Docker Image
+        uses: docker/build-push-action@v5
+        with:
+          context: ./nvim/tools
+          push: true
+          platforms: linux/amd64,linux/arm64
+          tags: |
+            https://gitea.setlock.net/shaun/dotfiles:latest
+            https://gitea.setlock.net/shaun/dotfiles:${{ env.GIT_TAG }}