[7.10] [meta] enable metricbeat upgrade test (#940) (#950)

This commit enable Metricbeat upgrade test which where disable before
7.10.0 release because Metricbeat 7.10.0 introduce breaking change
preventing upgrade from previous version.

Version post 7.10.0 will now be tested for upgrade from 7.10.0.

helpers/matrix.yml

@@ -26,7 +26,7 @@ METRICBEAT_SUITE:
   - default
   - oss
   - security
-  #- upgrade TODO: uncomment after 7.10.0 release
+  - upgrade
 LOGSTASH_SUITE:
   - default
   - oss

metricbeat/examples/upgrade/Makefile

@@ -4,7 +4,7 @@ include ../../../helpers/examples.mk
 
 CHART := metricbeat
 RELEASE := helm-metricbeat-upgrade
-#FROM := 7.10.0	# upgrade from version < 7.10.0 is failing due to selector
+FROM := 7.10.0	# upgrade from version < 7.10.0 is failing due to selector
 								# breaking change in https://github.com/elastic/helm-charts/pull/516
 
 install:
@@ -13,8 +13,7 @@ install:
 	kubectl rollout status deployment $(RELEASE)-metricbeat-metrics
 	kubectl rollout status deployment $(RELEASE)-kube-state-metrics
 
-#TODO: uncomment after 7.10.0 release
-test: #install goss
+test: install goss
 
 purge:
 	helm del $(RELEASE)