Introduce CI/CD to verify the basic functionality

[RinHizakura]

Since more people may be involved in providing necessary new features, we need to consider whether to set up basic CI/CD tests to ensure that no regression will occur after any changes are introduced.

[fabiomurer]

I can help by implementing github actions for formatting and compiling the source code but for the testing of the correct implementation of the protocol i don't have any good ideas how to do it.
Do you have a plan on how to approach this problem?

[RinHizakura]

We can start by the formatting and compilation. Even with that coverage only, it's still good.

For the functionality test of gdbstub, I plan to fork a simple and reliable emulator(e.g., semu, then use a script like https://github.com/sysprog21/rv32emu/blob/master/.ci/gdbstub-test.sh to test by matching the expected pattern, but this is just a first thought, and any idea is welcome, actually. If we can have a simpler emulator for testing purposes, that can also be great.

[fabiomurer]

i created the #13 with some basic functionalities, i plan to add more features after you tell me what you think

[RinHizakura]

Thanks to @fabiomurer 's contribution, now we have basic automated testing. Right now, I plan to maintain a few simple programs like test.c, and then fill in the unsupported instructions in the example emu. In this way, we can do some tests for mini-gdbstub directly through emu.

I want to make emu minimalist, because the first aim of this subproject is to show users how to use this library. So let's just support those instructions that we may find in our output from tests under test.