Potential fix for code scanning alert no. 1: Missing regular expressi…

…on anchor (#15)

Why
===
* Code scanning noted this regex was missing an anchor to protect against sanitation. This is low risk because these plugins are coming from the CLI, but let's fix it anyway.

What changed
===
* Add start and end of line anchors

Test plan
===
* CI passes

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

cmd/eiam/plugins.go

@@ -91,7 +91,7 @@ func newCmdPluginsInstall() *cobra.Command {
 			with. See 'eiam plugins auth --help' for more details.
 		`),
 		Args: func(cmd *cobra.Command, args []string) error {
-			urlRegex := regexp.MustCompile(`github\.com/(?P<user>[[:alnum:]\-]+)/(?P<repo>[[:alnum:]\.\-_]+)`)
+			urlRegex := regexp.MustCompile(`^github\.com/(?P<user>[[:alnum:]\-]+)/(?P<repo>[[:alnum:]\.\-_]+)$`)
 			match := urlRegex.FindStringSubmatch(url)
 			if match == nil {
 				err := fmt.Errorf("%s is not a valid Github repo URL", url)