Add a notice indicating that the charm is deprecated

Change-Id: I768cca3c55c636a14d0eb6f026d8d745e6f70a5d

README.md

@@ -4,6 +4,8 @@ The ceph-iscsi charm deploys the [Ceph iSCSI gateway
 service][ceph-iscsi-upstream]. The charm is intended to be used in conjunction
 with the [ceph-osd][ceph-osd-charm] and [ceph-mon][ceph-mon-charm] charms.
 
+**NOTE**: This charm is deprecated. No new features will be introduced.
+
 # Usage
 
 ## Configuration

osci.yaml

@@ -23,25 +23,25 @@
       - name: tox-py310
         soft: true
     vars:
-      tox_extra_args: jammy
+      tox_extra_args: -- jammy
 - job:
     name: ceph-iscsi-jammy-quincy-ec
     parent: func-target
     dependencies:
       - ceph-iscsi-jammy-quincy
     vars:
-      tox_extra_args: jammy-ec
+      tox_extra_args: -- jammy-ec
 - job:
     name: ceph-iscsi-kinetic-quincy
     parent: func-target
     dependencies:
       - ceph-iscsi-jammy-quincy
     vars:
-      tox_extra_args: kinetic
+      tox_extra_args: -- kinetic
 - job:
     name: ceph-iscsi-kinetic-quincy-ec
     parent: func-target
     dependencies:
       - ceph-iscsi-jammy-quincy
     vars:
-      tox_extra_args: kinetic-ec
+      tox_extra_args: -- kinetic-ec

requirements.txt

@@ -1,6 +1,6 @@
 # requirements
+ops <= 1.6.0
 git+https://github.com/juju/charm-helpers.git#egg=charmhelpers
-git+https://github.com/canonical/operator.git#egg=ops
 git+https://opendev.org/openstack/charm-ops-interface-ceph-client#egg=interface_ceph_client
 git+https://opendev.org/openstack/charm-ops-openstack#egg=ops_openstack
 git+https://opendev.org/openstack/charm-ops-interface-tls-certificates#egg=interface_tls_certificates