gh-533 - Added codecov to the project badges.
gh-533 - Added codecov to the project badges.

GovernmentCommunicationsHeadquarters/Gaffer,gchq/Gaffer,GovernmentCommunicationsHeadquarters/Gaffer,gchq/Gaffer,gchq/Gaffer,GovernmentCommunicationsHeadquarters/Gaffer,GovernmentCommunicationsHeadquarters/Gaffer,gchq/Gaffer