python: doc: remove GPG signature, which is no longer supported by pypi

Author: cejkato2

pycommon/README-RPM-release.md

@@ -8,20 +8,15 @@
    ```
 
 3. create python src package using `python setup.py sdist`
-4. sign package(s) in `dist/` using:
 
-   ```
-   for i in *; do gpg2 --detach-sign -a "$i"; done
-   ```
-
-5. upload files in `dist/` using `twine`:
+4. upload files in `dist/` using `twine`:
 
    ```
    twine upload ./*
    ```
 
-6. run `make rpm`
-7. your packages are in `RPMBUILD/`, build for other RPM-based systems can be done using:
+5. run `make rpm`
+6. your packages are in `RPMBUILD/`, build for other RPM-based systems can be done using:
 
    ```
    copr build @CESNET/NEMEA RPMBUILD/SRPMS/<package.src.rpm>