Improve CI workflows

[User344]

In this PR I changed event type due to number of reasons:

• Main reason is to allow CI workflow to run for PRs that are based on branches in forks.
• Also fixes issue where CI wouldn't have ran if merging is not possible due to conflicts (we didn't run into this though).

And I also bumped ubuntu runner version to 24.04 (latest) to get rid of a warning in logs.

[User344]

Added installing of protoc 29.1 to fix issue in #27

[SamuelSarle]

LGTM.

Sidenote while we're looking at this file:
Is this correct?:

      - name: Run tests
        id: run-tests
        if: ${{ steps.check-tests.outcome == 'success' }}
        run: |
          cargo +${{ steps.install-rust.outputs.name }} test --target ${{ matrix.target }} --workspace --test "*" --no-fail-fast

It seems like providing --test "*" means that it only runs tests found in **/tests/*.rs but doesn't test anything in src/ folders. See the difference in output of cargo test --test "*" and cargo test in repo root folder.
Also if you give it a bogus name it lists only the four tests in tests/*.rs files:

$ cargo test --test "foobar"

error: no test target named `foobar`.
Available test targets:
    mpsc
    zst
    json_roundtrip
    function_block

[artob]

LGTM

[User344]

LGTM.

Sidenote while we're looking at this file: Is this correct?:

      - name: Run tests
        id: run-tests
        if: ${{ steps.check-tests.outcome == 'success' }}
        run: |
          cargo +${{ steps.install-rust.outputs.name }} test --target ${{ matrix.target }} --workspace --test "*" --no-fail-fast

It seems like providing --test "*" means that it only runs tests found in **/tests/*.rs but doesn't test anything in src/ folders. See the difference in output of cargo test --test "*" and cargo test in repo root folder. Also if you give it a bogus name it lists only the four tests in tests/*.rs files:

$ cargo test --test "foobar"

error: no test target named `foobar`.
Available test targets:
    mpsc
    zst
    json_roundtrip
    function_block

Good catch! It is indeed a little bit wrong!
For context:
Running cargo test will not only run tests, but also doctests (obviously) but also it will compile(not run) examples for some reason. Meaning that if there are issues with examples, both "Run tests" and "Build examples" steps will fail, though there is nothing wrong with tests!
That's exactly why --test "*" argument was introduced. Quotes are required so shell doesn't treat it as glob. And when Cargo encounters it, it will only run the tests, and tests only. Now I am not quite sure why I decided to test tests only without doctests back then...
Either way, good job on noticing and testing this! I will start working on a fix now.