Update kubectl in Dockerfile

Dockerfile

@@ -13,7 +13,7 @@ ADD https://github.com/fluxcd/flux2/releases/download/v0.25.3/flux_0.25.3_linux_
 COPY ./requirements.txt /requirements.txt
 RUN \
   # Install kubectl from alpine edge until alpine 3.16 is released
-  apk --no-cache add kubectl=~1.23.3-r0 \
+  apk --no-cache add kubectl=~1.23.4-r0 \
     --repository=http://dl-cdn.alpinelinux.org/alpine/edge/testing && \
   apk --no-cache add \
     bash=~5.1.8-r0 \