fix: zeronet/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-ALPINE314-EXPAT-2342147
- https://snyk.io/vuln/SNYK-ALPINE314-EXPAT-2342148
- https://snyk.io/vuln/SNYK-ALPINE314-EXPAT-2342152
- https://snyk.io/vuln/SNYK-ALPINE314-EXPAT-2342153
- https://snyk.io/vuln/SNYK-ALPINE314-EXPAT-2342154

zeronet/Dockerfile

@@ -1,4 +1,4 @@
-FROM python:rc-alpine
+FROM python:3.10-alpine3.14
 
 #Base settings
 ENV HOME /root