fix Transfer-Encoding "chunked" on empty responses
diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8422e87c7a26a..74a6e20f022ca 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -110,8 +110,7 @@ jobs:
             TEST_PATH: "tests/integration/awslambda/ tests/integration/test_integration.py"
             PYTEST_ARGS: "--reruns 2 --junitxml=target/reports/lambda-docker.xml -o junit_suite_name='lambda-docker'"
             COVERAGE_ARGS: "-p"
-          # TODO: re-enable the tests below!
-          command: make test-coverage || true
+          command: make test-coverage
       - run:
           name: Test 'docker-reuse' Lambda executor
           environment:
@@ -120,8 +119,7 @@ jobs:
             TEST_PATH: "tests/integration/awslambda/ tests/integration/test_integration.py"
             PYTEST_ARGS: "--reruns 2 --junitxml=target/reports/lambda-docker-reuse.xml -o junit_suite_name='lambda-docker-reuse'"
             COVERAGE_ARGS: "-p"
-          # TODO: re-enable the tests below!
-          command: make test-coverage || true
+          command: make test-coverage
       - run:
           name: Store coverage results
           command: mv .coverage.* target/coverage/
diff --git a/setup.cfg b/setup.cfg
index 43c5985ba7da7..5bc18deb1e169 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -85,15 +85,12 @@ runtime =
     moto-ext[all]==3.1.2
     opensearch-py>=1.0.0
     pproxy>=2.7.0
-    #pympler>=0.6
     pyopenssl>=21.0.0
     Quart>=0.6.15
-    # Pin Jinja2 (transitive dep of Quart) until this bug is fixed: https://github.com/pgjones/quart/issues/141
-    Jinja2<=3.0.3
     readerwriterlock>=1.0.7
     requests-aws4auth==0.9
-    #sasl>=0.2.1
-    Werkzeug>=2.0
+    # Pin werkzeug until the issue discussed here is fixed: https://github.com/localstack/localstack/pull/5773
+    Werkzeug>=2.0,<2.1.0
     xmltodict>=0.11.0
 
 # @deprecated - use extra 'runtime' instead.

Avoid returning `Transfer-Encoding` headers for HTTP 204 responses. Should fix the currently failing build on `master`.

Currently seeing connection/protocol errors like below:
```
            except (HTTPException, SocketError) as e:
                # This includes IncompleteRead.
>               raise ProtocolError("Connection broken: %r" % e, e)
E               urllib3.exceptions.ProtocolError: ("Connection broken: InvalidChunkLength(got length b'', 0 bytes read)", InvalidChunkLength(got length b'', 0 bytes read))

.venv/lib/python3.8/site-packages/urllib3/response.py:458: ProtocolError
```

The issue is that `Transfer-Encoding` is being returned from some of the Flask APIs (Lambda DELETE operations that return a 204 status), which newer versions of `urllib3` cannot handle.

Was doing a quick search across recent changes in `urllib3`/`flask`/`hypercorn` to find out where this new behavior got introduced, but couldn't pinpoint the change so far.
 
The change to remove `Transfer-Encoding` seems safe in the general case, as 204 HTTP responses expect no content to be sent along with the response.