Get rid of `sed` usage inside Capact release pipeline scripts

[pkosiec]

Description

Refactor hack/make-release.sh and hack/release-charts.sh script:

• Get rid of error-prone sed usage

Alternatives:

• yq (however, it reformats the file, which could be a concern for some)
  • Implemented fully as a part of the Allow setting Dashboard image tag during Capact release #617 and reverted in 505bf6f
• rewrite the scripts to Go as suggested by @mszostok (and probably use some custom/different YAML parser)
  ​ - ???

See the discussion #617

Reason

The current solution is very shortsighted. In case of Dashboard tag, the current approach replaces any tag property, which is a generic word. It's a matter of time when we have such duplicated property in the values.yaml file. Same with other properties, like branch, which could occur multiple times, as we have multiple sources support in Populator. Should we build more complex sed one-liners in future? Definitely not, so that would need to be addressed.