Revert "ci: Change docker_release.yml workflow to run after successful PyPi release (#4293)" (#4513)

This reverts commit 6e241262ada9e59359d653a779246d2ad03c1223.

.github/workflows/docker_release.yml

@@ -1,13 +1,12 @@
 name: Docker image release
 
 on:
+  workflow_dispatch:
   push:
     branches:
       - main
-  workflow_run:
-    workflows: [Project release on PyPi]
-    types:
-      - completed
+    tags:
+      - "v[0-9].[0-9]+.[0-9]+*"
 
 env:
   DOCKER_REPO_NAME: deepset/haystack
@@ -15,8 +14,6 @@ env:
 jobs:
   build-and-push:
     name: Build ${{ matrix.target }} image for ${{ matrix.platform }}
-    # We need this to run only when we're merging in main or the PyPi release was successful
-    if: ${{ github.event_name == 'push' || github.event.workflow_run.conclusion == 'success' }}
     runs-on: ubuntu-latest
     strategy:
       matrix:

.github/workflows/pypi_release.yml

@@ -1,4 +1,3 @@
-# If you change this name also do it in docker_release.yml
 name: Project release on PyPi
 
 on: