checking out on latest commit on the pykmip repo

The image build was failing because we were trying to install pykmip
with python v2 (setup.py install uses python command which points to python v2
by default in alpine image). This change checks out the latest commit and
installs pykmip with pip3 as this is the one now supported by pykmip.
Issue: CLDSRV-806

Author: benzekrimaha

.github/pykmip/Dockerfile

@@ -17,9 +17,10 @@ RUN apk add --no-cache \
     pip3 install --upgrade typing-extensions>=4.13.2 && \
     git clone https://github.com/openkmip/pykmip.git && \
     cd pykmip && \
-    python3 setup.py install && \
+    git checkout 6cd44b572b0ca55adf01a8a12078b2284602e64c && \
+    pip3 install . && \
     apk del .build-deps && \
-    rm -rf /pykmip && \
+    rm -rf /var/cache/apk/* /pykmip && \
     mkdir /pykmip
 
 ADD ./bin /usr/local/bin