feat(gh-actions): add support for GitHub Actions (#37)

Author: jcrqr

README.md

@@ -76,6 +76,30 @@ bump libs/xyz from 0.0.0 to 0.1.0
 # creates a tag `libs/xyz/0.1.0`
 ```
 
+## Usage in GitHub Actions
+
+The following example shows a workflow using git-semver in GitHub Actions:
+
+```yaml
+name: Bump
+
+jobs:
+  bump:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          fetch-depth: 0
+
+      - uses: carlsberg/[email protected]
+        with:
+          script: |
+            echo "Latest Version: $(git semver latest)"
+            echo "Next Version: $(git semver next)"
+            
+            git semver bump -u ${{ github.actor }} -P ${{ github.token }}
+```
+
 ## License
 
 This project is released under the [MIT License](LICENSE).

action.yml

@@ -0,0 +1,32 @@
+name: Git SemVer
+description: Installs and runs git-semver
+
+inputs:
+  script:
+    description: Shell script to run
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - id: version
+      run: |
+        v="${{ github.action_ref }}"
+        v=$(echo "${v:1}")
+        echo "::set-output name=version::$v"
+      shell: bash
+
+    - run: |
+        v="${{ steps.version.outputs.version }}"
+        url="https://github.com/carlsberg/git-semver/releases/download/v$v/git-semver_$v_Linux_x86_64.tar.gz"
+        curl -L "$url" >> git-semver.tar.gz
+        tar -xvzf git-semver.tar.gz
+        mkdir $HOME/.local/bin && mv git-semver $HOME/.local/bin
+        echo $HOME/.local/bin >> $GITHUB_PATH
+      shell: bash
+
+    - run: |
+        echo '${{ inputs.runs }}' >> script.sh
+        chmod +x script.sh
+        ./script.sh
+      shell: bash