Allow getting versions for any package. (algorand#2935)

## Summary

Add an option to support version checking for arbitrary packages. This would allow us to deploy indexer releases at `algorand-releases/<channel>/indexer-*`

## Test Plan

Ran the command and see the correct regex:
```
~$ updater ver check -c nightly -p indexer
Checking for files matching: 'channel/nightly/indexer_nightly_linux-amd64_' in bucket algorand-releases
no updates found for channel 'nightly'
```

Author: winder

cmd/updater/versionCmd.go

@@ -28,20 +28,26 @@ import (
 var (
 	destFile        string
 	versionBucket   string
+	packageName     string
 	specificVersion uint64
 	semanticOutput  bool
 )
 
+// DefaultPackageName is the package we'll use by default.
+const DefaultPackageName = "node"
+
 func init() {
 	versionCmd.AddCommand(checkCmd)
 	versionCmd.AddCommand(getCmd)
 
-	checkCmd.Flags().StringVarP(&versionBucket, "bucket", "b", "", "S3 bucket containing updates.")
 	checkCmd.Flags().BoolVarP(&semanticOutput, "semantic", "s", false, "Human readable semantic version output.")
+	checkCmd.Flags().StringVarP(&packageName, "package", "p", DefaultPackageName, "Get version of specific package.")
+	checkCmd.Flags().StringVarP(&versionBucket, "bucket", "b", "", "S3 bucket containing updates.")
 
 	getCmd.Flags().StringVarP(&destFile, "outputFile", "o", "", "Path for downloaded file (required).")
-	getCmd.Flags().StringVarP(&versionBucket, "bucket", "b", "", "S3 bucket containing updates.")
 	getCmd.Flags().Uint64VarP(&specificVersion, "version", "v", 0, "Specific version to download.")
+	getCmd.Flags().StringVarP(&packageName, "package", "p", DefaultPackageName, "Get version of specific package.")
+	getCmd.Flags().StringVarP(&versionBucket, "bucket", "b", "", "S3 bucket containing updates.")
 	getCmd.MarkFlagRequired("outputFile")
 }
 
@@ -67,7 +73,7 @@ var checkCmd = &cobra.Command{
 		if err != nil {
 			exitErrorf("Error creating s3 session %s\n", err.Error())
 		} else {
-			version, _, err := s3Session.GetLatestUpdateVersion(channel)
+			version, _, err := s3Session.GetPackageVersion(channel, packageName, 0)
 			if err != nil {
 				exitErrorf("Error getting latest version from s3 %s\n", err.Error())
 			}
@@ -102,7 +108,7 @@ var getCmd = &cobra.Command{
 		if err != nil {
 			exitErrorf("Error creating s3 session %s\n", err.Error())
 		} else {
-			version, name, err := s3Session.GetUpdateVersion(channel, specificVersion)
+			version, name, err := s3Session.GetPackageVersion(channel, packageName, specificVersion)
 			if err != nil {
 				exitErrorf("Error getting latest version from s3 %s\n", err.Error())
 			}

util/s3/s3Helper.go

@@ -199,11 +199,6 @@ func makeS3Session(credentials *credentials.Credentials, bucket string) (helper
 	return
 }
 
-// GetLatestUpdateVersion returns the latest version details for the 'node' package
-func (helper *Helper) GetLatestUpdateVersion(channel string) (maxVersion uint64, maxVersionName string, err error) {
-	return helper.GetUpdateVersion(channel, 0)
-}
-
 // GetLatestPackageVersion returns the latest version details for a given package name (eg node, install, tools)
 func (helper *Helper) GetLatestPackageVersion(channel string, packageName string) (maxVersion uint64, maxVersionName string, err error) {
 	return helper.GetPackageVersion(channel, packageName, 0)
@@ -214,12 +209,6 @@ func (helper *Helper) GetLatestPackageFilesVersion(channel string, packagePrefix
 	return helper.GetPackageFilesVersion(channel, packagePrefix, 0)
 }
 
-// GetUpdateVersion ensures the specified version is present and returns the name of the file, if found
-// Or if specificVersion == 0, returns the name of the file with the max version
-func (helper *Helper) GetUpdateVersion(channel string, specificVersion uint64) (maxVersion uint64, maxVersionName string, err error) {
-	return helper.GetPackageVersion(channel, "node", specificVersion)
-}
-
 // DownloadFile downloads the specified file to the provided Writer
 func (helper *Helper) DownloadFile(name string, writer io.WriterAt) error {
 	downloader := s3manager.NewDownloader(helper.session)