Installing Go 1.18 beta1 errors

[leighmcculloch]

Description:
When installing Go 1.18 beta1, the install fails to find the binary even though it has been released.

Action version:
v2 which is at this time 331ce1d.

Platform:

• Ubuntu
• macOS
• Windows

Runner type:

• Hosted
• Self-hosted

Tools version:
Fails with both go1.18beta1 and go1.18.0-beta1.

Repro steps:
Demonstrated in this minimal PR: stellar/go#4143

Expected behavior:
Install Go 1.18 beta1.

Actual behavior:

Run actions/setup-go@v2
  with:
    go-version: 1.18beta1
    stable: true
    token: ***
Setup go stable version spec 1.18beta1
Attempting to download 1.18beta1...
matching 1.18beta1...
Not found in manifest.  Falling back to download directly from Go
Error: Unable to find Go version '1.18beta1' for platform linux and architecture x64.

Run actions/setup-go@v2
  with:
    go-version: 1.18.0-beta1
    stable: true
    token: ***
Setup go stable version spec 1.18.0-beta1
Attempting to download 1.18.0-beta1...
matching 1.18.0-beta1...
Not found in manifest.  Falling back to download directly from Go
Error: Unable to find Go version '1.18.0-beta1' for platform linux and architecture x64.

[leighmcculloch]

Turns out I needed to set the stable param to false as well.

     - name: Set up Go
       uses: actions/setup-go@v2
       with:
         go-version: ${{ matrix.go }}
         stable: ${{ !contains(matrix.go, 'beta') }}