chore(deps): update dependency ops to v2.13.0 (#99)

* chore(deps): update dependency ops to v2.13.0

* fix linting

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Arturo Seijas <arturo.seijas@canonical.com>
Co-authored-by: arturo-seijas <102022572+arturo-seijas@users.noreply.github.com>

requirements.txt

@@ -1,3 +1,3 @@
 cosl
-ops==2.12.0
+ops==2.13.0
 ops-lib-pgsql

src/charm.py

@@ -125,7 +125,7 @@ def _get_external_hostname(self) -> str:
         Returns:
             The assigned hostname.
         """
-        hostname = self.config["external_hostname"]
+        hostname = typing.cast(str, self.config["external_hostname"])
         if hostname == "":
             hostname = self.app.name
         return hostname
@@ -459,7 +459,7 @@ def _make_pod_env(self) -> Union[dict, bool, set, str]:
         Returns:
             A dictionary used for envConfig in podspec.
         """
-        env = self.model.config["environment"]
+        env = typing.cast(str, self.model.config["environment"])
 
         if not env:
             return {}