fix: disable nrfutil on arm64

See #25

Dockerfile

@@ -35,17 +35,13 @@ RUN mkdir /workdir/project && \
     python3 -m pip install --ignore-installed -U PyYAML && \
     #
     # Isolated command line tools
-    # No nrfutil 6+ release for arm64 (M1/M2 Macs), yet: https://github.com/NordicSemiconductor/pc-ble-driver-py/issues/227
+    # No nrfutil 6+ release for arm64 (M1/M2 Macs) and Python 3, yet: https://github.com/NordicSemiconductor/pc-ble-driver-py/issues/227
     #
     case $arch in \
     "amd64") \
         PIPX_HOME=/opt/pipx PIPX_BIN_DIR=/usr/local/bin \
         pipx install 'nrfutil>=6.0.0' \
         ;; \
-    "arm64") \
-        PIPX_HOME=/opt/pipx PIPX_BIN_DIR=/usr/local/bin \
-        pipx install 'nrfutil<6.0.0' \
-        ;; \
     esac && \
     #
     # ClangFormat