Feature request: inline Cake script support💡

Many GitHub script actions support inline scripts i.e. Azure CLI task
```yaml
with:
inlineScript: |
az account show
az storage -h
```

When doing a Frosting bootstrapper workaround until #43 is solved I did something like
```yaml
- name: Create Script Bootstrapper
run: |
echo 'DotNetRun("build/Build.csproj", "--target=GitHub-Actions");' > build.cake

- name: Run Cake script
uses: cake-build/cake-action@v2
with:
cake-version: 4.0.0
```
and it struck me that it would be really useful for some scenarios to instead of a small utility shell script able to have a Cake script inline, above could then be
```yaml
- name: Run Inline Cake script
uses: cake-build/cake-action@v2
with:
cake-version: 4.0.0
inlineScript: |
DotNetRun("build/Build.csproj", "--target=GitHub-Actions");
```

In my mind, it could just work like a pre- & post-processor to the regular script handling, something like
1. generate temporary file name/path
2. pass inline script contents into temporary file name/path
3. pass temporary file name/path as script-path
4. clean up the temporary path

Start by reading the existing regular script handling in the action and how the script-path input is passed through. Compare that flow with the requested inlineScript preprocessing and cleanup steps. Done means a workflow can provide inlineScript to run Cake, while existing script-path workflows continue to work.

Written by the indexing model from the issue text.