Add annotation for specs repo users (#103)

* Add annotation for specs repo users

* Make it pop

main.go

@@ -269,6 +269,9 @@ func main() {
 	if err != nil {
 		log.Warnf("Failed to determine if Podfile is using Specs repo, error: %s", err)
 	} else {
+		if isUsingSpecsRepo {
+			addSpecsRepoAnnotation(cmdFactory)
+		}
 		tracker.Enqueue("step_cocoapods_install_podfile_used", analytics.Properties{
 			"step_execution_id":   envRepository.Get("BITRISE_STEP_EXECUTION_ID"),
 			"build_slug":          envRepository.Get("BITRISE_BUILD_SLUG"),

podfile.go

@@ -4,8 +4,16 @@ import (
 	"bufio"
 	"os"
 	"strings"
+
+	"github.com/bitrise-io/go-utils/v2/command"
 )
 
+const specsRepoWarning = `### CocoaPods tip
+Your Podfile is still using the Specs repo. Switch to the CDN source for **faster and more reliable** dependency installs!
+
+Learn more about the **one-line change** [here](https://blog.cocoapods.org/CocoaPods-1.8.0-beta/).
+`
+
 // isPodfileUsingSpecsRepo returns true if the Podfile contains a source 'https://github.com/CocoaPods/Specs.git'.
 // It returns false if the CDN source or any other 3rd party git source is used.
 func isPodfileUsingSpecsRepo(path string) (bool, error) {
@@ -33,3 +41,8 @@ func isPodfileUsingSpecsRepo(path string) (bool, error) {
 
 	return specsRepoDefined, nil
 }
+
+func addSpecsRepoAnnotation(cmdFactory command.Factory) {
+	cmd := cmdFactory.Create("bitrise", []string{":annotations", "annotate", specsRepoWarning, "--style", "info"}, nil)
+	_ = cmd.Run() // ignore error, this is best-effort
+}