Set main as the default branch (#527)

* set main as the default branch

* revert change to tool-cache default branch

* use versions where applicable

.github/workflows/artifact-tests.yml

@@ -2,7 +2,7 @@ name: artifact-unit-tests
 on:
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - '**.md'
   pull_request:

.github/workflows/audit.yml

@@ -2,7 +2,7 @@ name: toolkit-audit
 on:
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - '**.md'
   pull_request:

.github/workflows/cache-tests.yml

@@ -2,7 +2,7 @@ name: cache-unit-tests
 on:
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - '**.md'
   pull_request:

.github/workflows/unit-tests.yml

@@ -2,7 +2,7 @@ name: toolkit-unit-tests
 on:
   push:
     branches:
-      - master
+      - main
     paths-ignore:
       - '**.md'
   pull_request:

.github/workflows/update-github.yaml

@@ -37,7 +37,7 @@ jobs:
           script: |
             github.pulls.create(
             {
-              base: "master",
+              base: "main",
               owner: "${{github.repository_owner}}",
               repo: "toolkit",
               title: "Update Octokit dependencies",