use plugin cache for provider lock across for all platforms

The cache architecture already supports multi-platform, the only
downside is that this might grow the cache. This seems expected.

internal/command/providers_lock.go

@@ -249,8 +249,8 @@ func (c *ProvidersLockCommand) Run(args []string) int {
 
 		// Use global plugin cache for extra speed if this architecture matches the systems (and therefore the caches) one
 		globalCacheDir := c.providerGlobalCacheDir()
-		if globalCacheDir != nil && platform == getproviders.CurrentPlatform {
-			installer.SetGlobalCacheDir(globalCacheDir)
+		if globalCacheDir != nil {
+			installer.SetGlobalCacheDir(globalCacheDir.WithPlatform(platform))
 			installer.SetGlobalCacheDirMayBreakDependencyLockFile(c.PluginCacheMayBreakDependencyLockFile)
 		}
 

internal/providercache/dir.go

@@ -75,6 +75,12 @@ func (d *Dir) BasePath() string {
 	return filepath.Clean(d.baseDir)
 }
 
+// WithPlatform creates a new dir with the provided platform based
+// on this dir
+func (d *Dir) WithPlatform(platform getproviders.Platform) *Dir {
+	return NewDirWithPlatform(d.baseDir, platform)
+}
+
 // AllAvailablePackages returns a description of all of the packages already
 // present in the directory. The cache entries are grouped by the provider
 // they relate to and then sorted by version precedence, with highest