Update Koryphe version to 2.6.0 #2812

Job	Run time
Build Javadoc	1m 6s
Check all modules are tested	4s
Check Copyright Headers	30s
Check Markdown Links	34s
Tests (ubuntu-latest, Core, :gaffer2,:core,:access,:cache,:common-util,:data,:exception,:graph,:o...	1m 4s
Tests (ubuntu-latest, Accumulo, :accumulo-store,:accumulo-rest)	58s
Tests (ubuntu-latest, Federated-And-Map, :integration-test,:federated-store,:map-store,:map-rest,...	57s
Tests (ubuntu-latest, REST, :rest-api,:common-rest,:spring-rest,:core-rest,:store-implementation,...	57s
Tests (ubuntu-latest, Examples, :example,:basic,:basic-model,:basic-rest,:road-traffic,:road-traf...	1m 3s
Tests (ubuntu-latest, Big-Data-Libraries, :flink-library,:hdfs-library,:spark,:spark-library,:spa...	1m 0s
Tests (ubuntu-latest, Time-Library, :library,:time-library)	46s
Tests (ubuntu-latest, Caches, :cache-library,:sketches-library,:bitmap-library,:hazelcast-cache-s...	1m 11s
Tests (ubuntu-latest, Tinkerpop, :tinkerpop)	7s
Upload coverage to Codecov	0s
	10m 17s

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