fix: translations/es-ES/content/actions/creating-actions/dockerfile-s…

…upport-for-github-actions.md to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN9-APT-407402
- https://snyk.io/vuln/SNYK-DEBIAN9-GLIBC-356506
- https://snyk.io/vuln/SNYK-DEBIAN9-GLIBC-356506
- https://snyk.io/vuln/SNYK-DEBIAN9-GLIBC-356851
- https://snyk.io/vuln/SNYK-DEBIAN9-GLIBC-356851

translations/es-ES/content/actions/creating-actions/dockerfile-support-for-github-actions.md

@@ -66,7 +66,7 @@ ENTRYPOINT ["sh", "-c", "echo $GITHUB_SHA"]
 
 ```dockerfile
 # Container image that runs your code
-FROM debian:9.5-slim
+FROM debian:stretch-20210408-slim
 
 # Copies your code file from your action repository to the filesystem path `/` of the container
 COPY entrypoint.sh /entrypoint.sh