ci: reuse contrib free disk script

Author: kb-newrelic

.github/actions/free-disk-space/action.yaml

@@ -64,8 +64,7 @@ jobs:
         with:
           fetch-depth: 0 # required for tag metadata
 
-      - name: Free disk space
-        uses: ./.github/actions/free-disk-space
+      - run: ./scripts/free-disk-space.sh
 
       - name: Setup Go
         uses: actions/setup-go@v5

.github/workflows/ci-base.yaml

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+#
+# Copyright The OpenTelemetry Authors
+# SPDX-License-Identifier: Apache-2.0
+
+echo "Available disk space before:"
+df -h /
+
+# The Android SDK is the biggest culprit for the lack of disk space in CI.
+# It is installed into /usr/local/lib/android manually (ie. not with apt) by this script:
+# https://github.com/actions/runner-images/blob/main/images/ubuntu/scripts/build/install-android-sdk.sh
+# so let's delete the directory manually.
+echo "Deleting unused Android SDK and tools..."
+sudo rm -rf /usr/local/lib/android
+
+echo "Available disk space after:"
+df -h /