fix: docker/Dockerfile to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DEBIAN11-EXPAT-2403512
- https://snyk.io/vuln/SNYK-DEBIAN11-EXPAT-2406127
- https://snyk.io/vuln/SNYK-DEBIAN11-OPENSSL-2388380
- https://snyk.io/vuln/SNYK-DEBIAN11-OPENSSL-2426309
- https://snyk.io/vuln/SNYK-DEBIAN11-OPENSSL-2426309

docker/Dockerfile

@@ -9,7 +9,7 @@ ARG build_for=linux/amd64
 ##
 # base image (abstract)
 ##
-FROM --platform=$build_for python:3.9.9-slim-bullseye as base
+FROM --platform=$build_for python:3.10.3-slim-bullseye as base
 
 # N.B. The refs updated automagically every release via bumpversion
 # N.B. dbt-postgres is currently found in the core codebase so a value of dbt-core@<some_version> is correct