fix: Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN9-PYTHON27-340070
- https://snyk.io/vuln/SNYK-DEBIAN9-PYTHON27-341379
- https://snyk.io/vuln/SNYK-DEBIAN9-PYTHON35-1063181
- https://snyk.io/vuln/SNYK-DEBIAN9-PYTHON35-340072
- https://snyk.io/vuln/SNYK-DEBIAN9-PYTHON35-453739

Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:experimental
 
-FROM node:12.8.1-stretch
+FROM node:12.22-stretch
 
 RUN \
   --mount=id=apt-cache,type=cache,target=/var/cache/apt \