Update and fix dependency cache CI action step

[GCHQDeveloper314]

The dependency cache step is using v2 of the cache action, v3 is the latest. It is also not excluding Gaffer JARs from the cache. Gaffer JARs should be excluded because the presence of previous builds in the cache can caused inconsistent behaviour. It appears to have always been the intention to exclude these JARs but the current config doesn't work as expected. https://github.com/gchq/Gaffer/blob/1f8b7431870e5c276d2c8aa9f90eb9ab61eeecb3/.github/workflows/continuous-integration.yaml#L76 The cache is also not being used except for repeat runs of the CI over the same commit. The step returns the message Cache not found for input keys and all dependencies must be downloaded manually. It seems it should be possible to use caches from other branches, at least with the v3 version of the action.

An example configuration for the v3 version of the action for Maven can be found here.