feat: extract version action

.github/actions/checkout-head/action.yml

@@ -2,6 +2,7 @@ name: Checkout Head
 description: >
   Attempt to checkout a repository using the head ref. If it doesn't exist attempt to fallback to the 
   base ref. If it doesn't exist then use the default branch.
+  # TODO: Fall back to version configured by project instead of main
 
 inputs:
   fetch-depth:

.github/actions/utils/extract-version/action.yml

@@ -0,0 +1,28 @@
+name: Extract version from a file
+description: Extracts the specified version from a file
+
+inputs:
+  working-directory:
+    description: Directory in which the action will run
+    default: .
+  version-name:
+    description: Name of the version to extract e.g. 'crt-kotlin-version'
+  file-path:
+    description: Path to the file to search for the version in (relative to `working-directory`).
+  output-path:
+    description: Directory where the version will be saved. The action writes the found version to 'version.txt' inside this directory
+    default: .
+
+runs:
+  using: composite
+  steps:
+    - name: Extract version
+      working-directory: ${{inputs.working-directory}}
+      shell: bash
+      run: |
+        echo "Looking for version '${{inputs.version-name}}' in '${{inputs.file-path}}'"
+        version=$(awk -F'=' -v k="${{inputs.version-name}}" '$1 ~ "^"k"[[:space:]]*" { gsub(/[[:space:]]*/, "", $2); gsub(/"/,"",$2); print $2 }' ${{inputs.file-path}})
+        echo "Found version '$version'"
+
+        echo "Saving version to '${{inputs.output-path}}/version.txt'"
+        echo "$version" > ${{inputs.output-path}}/version.txt