enable Go in test CI matrix

I'm assuming the default version of Go on the GitHub worker image will be
sufficient; if not, we can install a different one explicitly.

I'm not enabling the async tests for Go yet, since that will require publishing
and installing a build of Go with [this
patch](dicej/go@a1c8322);
I'll need to do some homework to find out the best way to do that.

Signed-off-by: Joel Dice <joel.dice@fermyon.com>

Author: dicej

.github/workflows/main.yml

@@ -59,7 +59,7 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         # moonbit removed from language matrix for now - causing CI failures
-        lang: [c, rust, csharp, cpp]
+        lang: [c, rust, csharp, cpp, go]
         exclude:
           # For now csharp doesn't work on macos, so exclude it from testing.
           - os: macos-latest