Release CLI Get doesn't encode tag-name
### Summary
The release CLI utility doesn't encode tag names correctly when hitting GET API.
### Steps to reproduce
1. Create a tag of format `abc/xyz`.
2. Create a release with the given tag-name
3. Use release-cli to get the release based on tag-name `abc/xyz`
```bash
./release-cli get --tag-name abc/xyz
```
### What is the current *bug* behavior?
This will result in 404 instead of the correct release object.
### What is the expected *correct* behavior?
It should fetch the correct release.
### Output of checks
This bug happens on GitLab.com
### Possible fixes
We should encode the URL Parameters correctly. In our use-case `/` becomes `%2F`
<!-- DO NOT CHANGE -->
~"devops::release" ~"group::release" ~"GitLab Release CLI" ~"Category:Release Orchestration"
issue