Merge pull request opencontainers#1029 from vbatts/pullapprove

PullApprove: No need for 3 DCO checks

Author: hqhq

.pullapprove.yml

@@ -2,7 +2,7 @@ version: 2
 
 requirements:
   signed_off_by:
-    required: true
+    required: false
 
 group_defaults:
   required: 2

Makefile

@@ -72,7 +72,7 @@ endif
 .gitvalidation:
 	@which git-validation > /dev/null 2>/dev/null || (echo "ERROR: git-validation not found. Consider 'make install.tools' target" && false)
 ifdef TRAVIS_COMMIT_RANGE
-	git-validation -q -run DCO,short-subject,dangling-whitespace
+	git-validation -q -run short-subject,dangling-whitespace
 else
 	git-validation -v -run DCO,short-subject,dangling-whitespace -range $(EPOCH_TEST_COMMIT)..HEAD
 endif