Bump feedgen from 0.7.0 to 1.0.0 in /server

Bumps [feedgen](https://github.com/lkiesow/python-feedgen) from 0.7.0 to 1.0.0.
- [Release notes](https://github.com/lkiesow/python-feedgen/releases)
- [Commits](lkiesow/python-feedgen@v0.7.0...v1.0.0)

---
updated-dependencies:
- dependency-name: feedgen
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

server/requirements.in

@@ -1,6 +1,6 @@
 gunicorn
 honcho
-feedgen==0.7.0
+feedgen==1.0.0
 openpyxl==3.0.7
 
 git+https://github.com/superdesk/superdesk-core.git@hotfix/2.6.8#egg=superdesk-core

server/requirements.txt

@@ -92,7 +92,7 @@ eve-elastic==7.3.2
     # via superdesk-core
 events==0.3
     # via eve
-feedgen==0.7.0
+feedgen==1.0.0
     # via -r requirements.in
 feedparser==6.0.11
     # via superdesk-core