Use version from module and another version in matrix testing about setup-go

[aparnajyothi-y]

Hello @Jacalz,
Thank you for creating this issue, we will investigate it and come back to you as soon as we have some feedback.

[myaaaaaaaaa]

An (untested) proof-of-concept:

diff --git a/src/main.ts b/src/main.ts
index 690d277..2fdeb8a 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -133,24 +133,27 @@ export function parseGoVersion(versionString: string): string {
   // fmt.Printf("go version %s %s/%s\n", runtime.Version(), runtime.GOOS, runtime.GOARCH)
   // expecting go<version> for runtime.Version()
   return versionString.split(' ')[2].slice('go'.length);
 }
 
 function resolveVersionInput(): string {
   let version = core.getInput('go-version');
-  const versionFilePath = core.getInput('go-version-file');
+  let versionFilePath = core.getInput('go-version-file');
 
   if (version && versionFilePath) {
     core.warning(
       'Both go-version and go-version-file inputs are specified, only go-version will be used'
     );
   }
 
   if (version) {
-    return version;
+    if (!version.endsWith('go.mod')) {
+      return version;
+    }
+    versionFilePath = version;
   }
 
   if (versionFilePath) {
     if (!fs.existsSync(versionFilePath)) {
       throw new Error(
         `The specified go version file at: ${versionFilePath} does not exist`
       );