Updating README to reflect newly supported endpoints (#446)

README.md

@@ -23,8 +23,8 @@ to add new and/or missing endpoints. Currently the following services are suppor
 - [x] Award Emojis
 - [x] Branches
 - [x] Broadcast Messages
-- [ ] Project-level Variables
-- [ ] Group-level Variables
+- [x] Project-level Variables
+- [x] Group-level Variables
 - [x] Commits
 - [ ] Custom Attributes
 - [x] Deployments
@@ -42,8 +42,9 @@ to add new and/or missing endpoints. Currently the following services are suppor
 - [x] Group Members
 - [x] Issues
 - [x] Issue Boards
+- [x] Group Issue Boards 
 - [x] Jobs
-- [ ] Keys
+- [x] Keys
 - [x] Labels
 - [ ] License
 - [x] Merge Requests