Update charmcraft.yaml for 1.7/2.0

The CHARMCRAFT_* vars changed to CRAFT_* and there has to be a
file that is the 'entrypoint', a concept somewhat lost on reactive
charms.  At some point, update charm-tools to build an entry point.

Change-Id: I86bef3d7cedb17a68539aad25ee6fe273da4b8cc

charmcraft.yaml

@@ -2,33 +2,32 @@ type: charm
 
 parts:
   charm:
+    charm-entrypoint: "hooks/install"
     build-packages:
       - tox
       - git
       - python3-dev
+      - libffi-dev
       - libmysqlclient-dev  # for executable mysql_shell
     override-build: |
       apt-get install ca-certificates -y
       tox -e build-reactive
     override-stage: |
-      echo "Copying charm to staging area: $CHARMCRAFT_STAGE"
-      NAME=$(ls $CHARMCRAFT_PART_BUILD/build/builds)
-      cp -r $CHARMCRAFT_PART_BUILD/build/builds/$NAME/* $CHARMCRAFT_STAGE/
+      echo "Copying charm to staging area: $CRAFT_STAGE"
+      NAME=$(ls $CRAFT_PART_BUILD/build/builds)
+      cp -r $CRAFT_PART_BUILD/build/builds/$NAME/* $CRAFT_STAGE/
     override-prime: |
       # For some reason, the normal priming chokes on the fact that there's a
       # hooks directory.
-      cp -r $CHARMCRAFT_STAGE/* .
+      cp -r $CRAFT_STAGE/* .
 
 bases:
   - build-on:
       - name: ubuntu
-        channel: "20.04"
+        channel: "22.04"
         architectures:
           - amd64
     run-on:
-      - name: ubuntu
-        channel: "20.04"
-        architectures: [amd64, s390x, ppc64el, arm64]
       - name: ubuntu
         channel: "22.04"
         architectures: [amd64, s390x, ppc64el, arm64]

osci.yaml

@@ -12,6 +12,7 @@
       needs_charm_build: true
       charm_build_name: mysql-innodb-cluster
       build_type: charmcraft
+      charmcraft_channel: "1.7/stable"
 
 - job:
     name: full_model-focal-full-ha

requirements.txt

@@ -10,7 +10,8 @@ setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb
 
 # Build requirements
 cffi==1.14.6; python_version < '3.6'  # cffi 1.15.0 drops support for py35.
-charm-tools==2.8.3
+charm-tools==2.8.3; python_version < '3.10'
+charm-tools; python_version >= '3.10'
 
 simplejson