Excavator: Update conjure plugins and dependencies (#385)

Author: svc-excavator-bot

versions.props

@@ -11,7 +11,7 @@ org.mockito:mockito-core = 1.9.5
 org.slf4j:* = 1.7.12
 one.util:streamex = 0.6.8
 org.assertj:assertj-core = 3.13.2
-com.palantir.conjure:conjure = 4.6.2
+com.palantir.conjure:conjure = 4.7.0
 com.palantir.conjure.java:* = 4.5.0
 com.fasterxml.jackson.dataformat:* = 2.9.9
 one.util:streamex = 0.6.8