fix(build): install Poetry via apk instead of pip (#2488)

The switch from `google/cloud-sdk:449.0.0-alpine` to
`gcr.io/google.com/cloudsdktool/google-cloud-cli:alpine` was not a
drop-in replacement:

This moved from Alpine 3.18.4 to 3.20.2 and 3.20.2 is more intolerant of
the `pip install poetry==1.8.3` being performed:

```
error: externally-managed-environment
```

Install Poetry via `apk` instead.

vulnfeeds/tools/debian/Dockerfile

@@ -18,8 +18,7 @@ FROM gcr.io/google.com/cloudsdktool/google-cloud-cli:alpine@sha256:d5da0344b23d0
 # this project as it runs on kubernetes, but it keeps it consistent with other cloud run images
 ENV POETRY_VIRTUALENVS_IN_PROJECT=true
 
-RUN apk --no-cache add py3-pip \
-    && pip install poetry==1.8.3
+RUN apk --no-cache add poetry
 
 RUN mkdir /src
 WORKDIR /src