chore(jenkins): Update Jenkins plugins (#1220)

Author: gounthar

dockerfiles/plugins.txt

@@ -23,7 +23,7 @@ git:5.7.0
 github-api:1.321-488.v9b_c0da_9533f8
 github-branch-source:1815.v9152b_2ff7a_1b_
 github:1.43.0
-gradle:2.14.1
+gradle:2.15
 instance-identity:203.v15e81a_1b_7a_38
 ionicons-api:88.va_4187cb_eddf1
 jackson2-api:2.18.3-402.v74c4eb_f122b_2
@@ -71,7 +71,7 @@ token-macro:444.v52de7e9c573d
 trilead-api:2.209.v0e69b_c43c245
 variant:70.va_d9f17f859e0
 workflow-aggregator:608.v67378e9d3db_1
-workflow-api:1371.ve334280b_d611
+workflow-api:1373.v7b_813f10efa_b_
 workflow-basic-steps:1079.vce64b_a_929c5a_
 workflow-cps:4106.v7a_8a_8176d450
 workflow-durable-task-step:1405.v1fcd4a_d00096