Set main as the default branch (#527)

* set main as the default branch

* revert change to tool-cache default branch

* use versions where applicable

docs/action-types.md

@@ -32,14 +32,14 @@ jobs:
         os: [ubuntu-16.04, windows-2019]
     runs-on: ${{matrix.os}}
     actions:
-    - uses: actions/setup-node@master
+    - uses: actions/setup-node@v1
       with:
         version: ${{matrix.node}}
     - run: | 
         npm install
     - run: |
         npm test
-    - uses: actions/custom-action@master
+    - uses: actions/custom-action@v1
 ```
 
 JavaScript actions work on any environment that host action runtime is supported on which is currently node 12.  However, a host action that runs a toolset expects the environment that it's running on to have that toolset in its PATH or using a setup-* action to acquire it on demand.

docs/action-versioning.md

@@ -17,13 +17,13 @@ Binding to a major version is the latest of that major version ( e.g. `v1` == "1
 
 Major versions should guarantee compatibility.  A major version can add net new capabilities but should not break existing input compatibility or break existing workflows. 
 
-Major version binding allows you to take advantage of bug fixes and critical functionality and security fixes.  The `master` branch has the latest code and is unstable to bind to since changes get committed to master and released to the market place by creating a tag.  In addition, a new major version carrying breaking changes will get implemented in master after branching off the previous major version.
+Major version binding allows you to take advantage of bug fixes and critical functionality and security fixes.  The `main` branch has the latest code and is unstable to bind to since changes get committed to main and released to the market place by creating a tag.  In addition, a new major version carrying breaking changes will get implemented in main after branching off the previous major version.
 
-> Warning: do not reference `master` since that is the latest code and can be carrying breaking changes of the next major version.
+> Warning: do not reference `main` since that is the latest code and can be carrying breaking changes of the next major version.
 
 ```yaml
 steps:
-    - uses: actions/javascript-action@master  # do not do this
+    - uses: actions/javascript-action@main  # do not do this
 ```
 
 Binding to the immutable full sha1 may offer more reliability.  However, note that the hosted images toolsets (e.g. ubuntu-latest) move forward and if there is a tool breaking issue, actions may react with a patch to a major version to compensate so binding to a specific SHA may prevent you from getting fixes.

docs/commands.md

@@ -1,6 +1,6 @@
 # :: Commands
 
-The [core toolkit package](https://github.com/actions/toolkit/tree/master/packages/core) offers a number of convenience functions for
+The [core toolkit package](https://github.com/actions/toolkit/tree/main/packages/core) offers a number of convenience functions for
 setting results, logging, registering secrets and exporting variables across actions. Sometimes, however, its useful to be able to do
 these things in a script or other tool.
 

docs/container-action.md

@@ -18,7 +18,7 @@ e.g. To use https://github.com/actions/setup-node, users will author:
 
 ```yaml
 steps:
-    using: actions/setup-node@master
+    using: actions/setup-node@v1
 ```
 
 # Define Metadata

docs/problem-matchers.md

@@ -111,10 +111,10 @@ Registering two problem-matchers with the same owner will result in only the pro
 ## Examples
 
 Some of the starter actions are already using problem matchers, for example:
-- [setup-node](https://github.com/actions/setup-node/tree/master/.github)
-- [setup-python](https://github.com/actions/setup-python/tree/master/.github)
-- [setup-go](https://github.com/actions/setup-go/tree/master/.github)
-- [setup-dotnet](https://github.com/actions/setup-dotnet/tree/master/.github)
+- [setup-node](https://github.com/actions/setup-node/tree/main/.github)
+- [setup-python](https://github.com/actions/setup-python/tree/main/.github)
+- [setup-go](https://github.com/actions/setup-go/tree/main/.github)
+- [setup-dotnet](https://github.com/actions/setup-dotnet/tree/main/.github)
 
 ## Troubleshooting