chore: migrate to main branch (googleapis#706)

* chore: migrate to main branch

* 🦉 Updates from OwlBot

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* use latest post processor image

* remove obsolete replacements in owlbot.py

* update post processor image

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>
Co-authored-by: Anthonios Partheniou <[email protected]>

Author: 3 people

.github/.OwlBot.lock.yaml

@@ -5,5 +5,5 @@
 # https://developers.google.com/open-source/licenses/bsd
 
 docker:
-  image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:82d046d572a11b84d64d4b9af93ad55a1b6a4854917504ba7557acdfce907dde
+  image: gcr.io/repo-automation-bots/owlbot-python:latest
+  digest: sha256:0ffe3bdd6c7159692df5f7744da74e5ef19966288a6bf76023e8e04e0c424d7d

.github/workflows/django_tests_against_emulator0.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests0
 jobs:

.github/workflows/django_tests_against_emulator1.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests1
 jobs:

.github/workflows/django_tests_against_emulator2.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests2
 jobs:

.github/workflows/django_tests_against_emulator3.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests3
 jobs:

.github/workflows/django_tests_against_emulator4.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests4
 jobs:

.github/workflows/django_tests_against_emulator5.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests5
 jobs:

.github/workflows/django_tests_against_emulator6.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests6
 jobs:

.github/workflows/django_tests_against_emulator7.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests7
 jobs:

.github/workflows/django_tests_against_emulator8.yml

@@ -1,7 +1,7 @@
 on:
   push:
     branches:
-      - master
+      - main
   pull_request:
 name: django-tests8
 jobs: