Fix all open Dependabot Python alerts in Pipfiles (#8488)

## Summary
This PR addresses all currently open Dependabot alerts in this
repository by updating vulnerable Python dependencies in both mirrored
regression-test environments:

- src/test/regress/Pipfile / Pipfile.lock
- .devcontainer/src/test/regress/Pipfile / Pipfile.lock

## Updated dependencies
- cryptography: 44.0.3 -> 46.0.5 (patched: >=46.0.5)
- Werkzeug: 3.1.4 -> 3.1.5 (patched: >=3.1.5)
- filelock: resolved to 3.25.0 (patched: >=3.20.3)
- pyasn1: resolved to 0.6.2 (patched: >=0.6.2)

## Alerts covered
Closes Dependabot alerts: #98, #99, #100, #101, #102, #103, #104, #105,
#106, #107, #108, #109.

## Notes
Lockfiles were regenerated with pipenv lock in both directories to
ensure consistent, hashed resolution.

Author: ihalatci

.devcontainer/Dockerfile

@@ -97,7 +97,7 @@ RUN cp -r .pgenv/src .pgenv/pgsql-* .pgenv/config .pgenv-staging/
 RUN rm .pgenv-staging/config/default.conf
 
 FROM base AS pg18
-RUN MAKEFLAGS="-j $(nproc)" pgenv build 18.1
+RUN MAKEFLAGS="-j $(nproc)" pgenv build 18.3
 RUN rm .pgenv/src/*.tar*
 RUN make -C .pgenv/src/postgresql-*/ clean
 RUN make -C .pgenv/src/postgresql-*/src/include install
@@ -216,7 +216,7 @@ COPY --chown=citus:citus .psqlrc .
 RUN sudo chown --from=root:root citus:citus -R ~
 
 # sets default pg version
-RUN pgenv switch 18.1
+RUN pgenv switch 18.3
 
 # make connecting to the coordinator easy
 ENV PGPORT=9700

.devcontainer/src/test/regress/Pipfile

@@ -16,7 +16,7 @@ tornado = ">=6.5.1,<6.6.0"
 zstandard = ">=0.25.0"
 construct = "*"
 docopt = "==0.6.2"
-cryptography = "==44.0.3"
+cryptography = "==46.0.5"
 pytest = "*"
 psycopg = "*"
 filelock = "*"
@@ -25,7 +25,7 @@ pytest-timeout = "*"
 pytest-xdist = "*"
 pytest-repeat = "*"
 pyyaml = "*"
-werkzeug = "==3.1.4"
+werkzeug = "==3.1.5"
 "typing-extensions" = ">=4.13.2,<5"
 pyperclip = "==1.9.0"