🐐 appeace bandint security warnings

In this particular case bandit was complaining about potential path
escape exploits on urlopen. However the urls are safe enough, because
all template parameters inserted into the url are from:

 * config.yml - malicious changes to config.yml are possible that's
   already a lot bigger issue than this than redirecting github api
   calls.
 * git tags witch are present in bot the local index-v2.json file (as
   versionName) and the remote github API. (git tags don't allow the
   string '..')

fdroidserver/github.py

@@ -51,7 +51,7 @@ class GithubApi:
         """List of all tags that are associated with a release for this repo on GitHub."""
         names = []
         req = self._req(f"https://api.github.com/repos/{self._repo_path}/releases")
-        with urllib.request.urlopen(req) as resp:
+        with urllib.request.urlopen(req) as resp:  # nosec CWE-22 disable bandit warning
             releases = json.load(resp)
             for release in releases:
                 names.append(release['tag_name'])
@@ -71,7 +71,7 @@ class GithubApi:
         req = self._req(
             f"https://api.github.com/repos/{self._repo_path}/git/matching-refs/tags/{tag}"
         )
-        with urllib.request.urlopen(req) as resp:
+        with urllib.request.urlopen(req) as resp:  # nosec CWE-22 disable bandit warning
             rd = json.load(resp)
             return len(rd) == 1 and rd[0].get("ref", False) == f"refs/tags/{tag}"
         return False
@@ -82,7 +82,7 @@ class GithubApi:
         req = self._req(
             f"https://api.github.com/repos/{self._repo_path}/git/matching-refs/tags/"
         )
-        with urllib.request.urlopen(req) as resp:
+        with urllib.request.urlopen(req) as resp:  # nosec CWE-22 disable bandit warning
             refs = json.load(resp)
             for ref in refs:
                 r = ref.get('ref', '')
@@ -118,7 +118,9 @@ class GithubApi:
             ).encode("utf-8"),
         )
         try:
-            with urllib.request.urlopen(req) as resp:
+            with urllib.request.urlopen(  # nosec CWE-22 disable bandit warning
+                req
+            ) as resp:
                 release_id = json.load(resp)['id']
         except urllib.error.HTTPError as e:
             if e.status == 422:
@@ -153,6 +155,6 @@ class GithubApi:
                 },
                 data=f.read(),
             )
-            with urllib.request.urlopen(req):
+            with urllib.request.urlopen(req):  # nosec CWE-22 disable bandit warning
                 return True
             return False