fix(slugbuilder-cache): fix typo in comments (#417)

a minor typo fix: sotrage -> storage

Author: aboyett

pkg/gitreceive/slug_builder_info.go

@@ -40,7 +40,7 @@ func (s SlugBuilderInfo) PushKey() string { return s.pushKey }
 // folder, not including the final filename.
 func (s SlugBuilderInfo) TarKey() string { return s.tarKey }
 
-// CacheKey returns the object sotrage key that the slug builder will use to store the cache in
+// CacheKey returns the object storage key that the slug builder will use to store the cache in
 // it's application specific and persisted between deploys (doesn't contain git-sha)
 func (s SlugBuilderInfo) CacheKey() string { return s.cacheKey }