unable to click always allow on git-credential-osxkeychain popup

This fixed the issue for me:

• Open Keychain Access
• Select Keychains -> login and Category -> Passwords
• Type github.com in search box, you should see an entry (or entries) of Internet Password kind for github.com. Right click & Delete them.
• Go back to terminal and retry the git command that requires the password
• Type in your git username and password when prompted
• Done 🙂