add pkg-config to test image (#1863)

* add pkg-config to test image

newest release of mysqlclient requires pkg-config to build.

I also had to switch netcat to netcat-traditional, as the netcat
package isn't available in the Python 3.11 base image

* Disable mysqlclient-newest

---------

Co-authored-by: Colton Myers <[email protected]>

Author: beniwohli

.ci/.matrix_exclude.yml

@@ -198,3 +198,6 @@ exclude:
     FRAMEWORK: grpc-1.24
   - VERSION: python-3.11
     FRAMEWORK: grpc-1.24
+  # temporary, see https://github.com/elastic/apm-agent-python/pull/1863
+  - VERSION: python-3.11
+    FRAMEWORK: mysqlclient-newest

tests/Dockerfile

@@ -7,9 +7,10 @@ RUN apt-get -qq update && apt-get -qq -y --no-install-recommends install \
     curl \
     gnupg2 \
     libmariadb-dev \
+    pkg-config \
     libpq-dev \
     make \
-    netcat \
+    netcat-traditional \
     odbc-postgresql \
     unixodbc-dev \
     freetds-dev \