Rename paas-app-charmer -> paas-charm (#1961)

The library
[`paas-app-charmer`](https://github.com/canonical/paas-app-charmer) has
been renamed to [`paas-charm`](https://github.com/canonical/paas-charm).

The change is backward compatible, as last version of the
`paas-app-charmer` will be empty and will point to the new version (and
will keep the old entrypoint classes).

This PR changes the references from paas-app-charm to paas-charm and
also the main charm module to the new location (`paas_app_charmer`
module renamed to `paas_charm`).

charmcraft/templates/init-django-framework/requirements.txt.j2

@@ -1,2 +1,2 @@
 ops ~= 2.17
-paas-app-charmer>=1.1,<2
+paas-charm>=1.0,<2

charmcraft/templates/init-django-framework/src/charm.py.j2

@@ -9,12 +9,12 @@ import typing
 
 import ops
 
-import paas_app_charmer.django
+import paas_charm.django
 
 logger = logging.getLogger(__name__)
 
 
-class {{ class_name }}(paas_app_charmer.django.Charm):
+class {{ class_name }}(paas_charm.django.Charm):
     """Django Charm service."""
 
     def __init__(self, *args: typing.Any) -> None:

charmcraft/templates/init-fastapi-framework/requirements.txt.j2

@@ -1,2 +1,2 @@
 ops ~= 2.17
-paas-app-charmer>=1.1,<2
+paas-charm>=1.0,<2

charmcraft/templates/init-fastapi-framework/src/charm.py.j2

@@ -9,12 +9,12 @@ import typing
 
 import ops
 
-import paas_app_charmer.fastapi
+import paas_charmer.fastapi
 
 logger = logging.getLogger(__name__)
 
 
-class {{ class_name }}(paas_app_charmer.fastapi.Charm):
+class {{ class_name }}(paas_charm.fastapi.Charm):
     """FastAPI Charm service."""
 
     def __init__(self, *args: typing.Any) -> None:

charmcraft/templates/init-flask-framework/requirements.txt.j2

@@ -1,2 +1,2 @@
 ops ~= 2.17
-paas-app-charmer>=1.1,<2
+paas-charm>=1.0,<2

charmcraft/templates/init-flask-framework/src/charm.py.j2

@@ -9,12 +9,12 @@ import typing
 
 import ops
 
-import paas_app_charmer.flask
+import paas_charm.flask
 
 logger = logging.getLogger(__name__)
 
 
-class {{ class_name }}(paas_app_charmer.flask.Charm):
+class {{ class_name }}(paas_charm.flask.Charm):
     """Flask Charm service."""
 
     def __init__(self, *args: typing.Any) -> None:

charmcraft/templates/init-go-framework/requirements.txt.j2

@@ -1,2 +1,2 @@
 ops ~= 2.17
-paas-app-charmer>=1.1,<2
+paas-charm>=1.0,<2

charmcraft/templates/init-go-framework/src/charm.py.j2

@@ -9,12 +9,12 @@ import typing
 
 import ops
 
-import paas_app_charmer.go
+import paas_charm.go
 
 logger = logging.getLogger(__name__)
 
 
-class {{ class_name }}(paas_app_charmer.go.Charm):
+class {{ class_name }}(paas_charm.go.Charm):
     """Go Charm service."""
 
     def __init__(self, *args: typing.Any) -> None: