release: use GitHub actions

[v1v]

What

Use GitHub actions in conjunction with the Buildkite GPG singing pipeline for the Release

Why

Remove support for Jenkins

Implementation details

GPG signing runs in Buildkite, that's the reason to use a Google Bucket to pass the unsinged binaries so they can be signed afterwards.

UI

Test

I ran this build using the test branch -> https://github.com/elastic/apm-agent-php/tree/test/migrate-jenkins

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 568b0bfb..ffbe2d5f 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -5,6 +5,8 @@ permissions:
   contents: read

 on:
+  ### TODO: For testing purposes
+  workflow_dispatch: ~
   create:
     tags: [ "v*" ]

@@ -110,14 +112,14 @@ jobs:

       - name: Create draft release
         run: |-
-          make -f .ci/Makefile draft-release
+          echo "make -f .ci/Makefile draft-release"
           echo "RELEASE_ID=$(make -f .ci/Makefile get-draft-release)" >> $GITHUB_ENV

       - name: Verify draft release
-        run: ORIGINAL_PACKAGES_LOCATION=build/packagesmake -f .ci/Makefile download-verify
+        run: echo "ORIGINAL_PACKAGES_LOCATION=build/packagesmake -f .ci/Makefile download-verify"

       - name: Publish release
-        run: make -f .ci/Makefile github-release-ready
+        run: echo "make -f .ci/Makefile github-release-ready"

   notify:
     if: always()
@@ -140,5 +142,5 @@ jobs:
           vaultUrl: ${{ secrets.VAULT_ADDR }}
           vaultRoleId: ${{ secrets.VAULT_ROLE_ID }}
           vaultSecretId: ${{ secrets.VAULT_SECRET_ID }}
-          slackChannel: "#apm-agent-php"
+          slackChannel: "#observablt-bots"
           message: "[${{ github.repository }}] Release (<${{ github.server_url }}/${{ github.repository }}/releases/tag/${{ github.ref_name }}|${{ github.ref_name }}>)"

[v1v]

I'm gonna refactor this PR so it can use the changes in https://github.com/elastic/apm-agent-php/pull/1058