chore(deps): update alpine docker tag to v3.11 (#70)

renovate[bot] · renovate-bot · web-flow · commit 2403de8c2b27 · 2020-03-10T23:45:24.000+11:00
Co-authored-by: Renovate Bot &lt;bot@renovateapp.com&gt;
diff --git a/Dockerfile b/Dockerfile
@@ -1,4 +1,4 @@
-FROM alpine:3.9
+FROM alpine:3.11
 
 ARG BUILD_DATE
 ARG VCS_REF
