Add Go 1.17 to the CI pipeline.
diff --git a/bitbucket-pipelines.yml b/bitbucket-pipelines.yml
index 8ff6f73..30bdba0 100644
--- a/bitbucket-pipelines.yml
+++ b/bitbucket-pipelines.yml
@@ -30,3 +30,6 @@
     - step:
         image: golang:1.16
         <<: *Verify
+    - step:
+        image: golang:1.17
+        <<: *Verify