deps(docker-compose): update camunda/identity docker tag to v8.7.15 (#336)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

docker-compose/versions/camunda-8.7/.env

@@ -4,7 +4,7 @@ CAMUNDA_CONNECTORS_VERSION=8.7.15
 # renovate: datasource=docker depName=camunda/zeebe
 CAMUNDA_ZEEBE_VERSION=8.7.23
 # renovate: datasource=docker depName=camunda/identity
-CAMUNDA_IDENTITY_VERSION=8.7.14
+CAMUNDA_IDENTITY_VERSION=8.7.15
 # renovate: datasource=docker depName=camunda/operate
 CAMUNDA_OPERATE_VERSION=8.7.23
 # renovate: datasource=docker depName=camunda/tasklist