Special handling of cmake scripts

[winksaville]

This fix only works with cmake, but I suspect other scripting languages
would have similar problems. I'm hoping there is a better solution, but
something like this does work for my particular problem.

The problem is having the first line of scripts be: Path="xxx:${PATH}"
where xxx is rc.ExtraPath, does not work for all scripting languages.
For example: 'cmake -P {0}' is used by Cristian Adam HelloWorld:
https://github.com/cristianadam/HelloWorld/blob/master/.github/workflows/build_cmake.yml#:~:text=shell:

Here is some test code:

name: CMake Build Matrix

on: [push, pull_request]

env:
CMAKE_VERSION: 3.18.3
NINJA_VERSION: 1.10.1
BUILD_TYPE: Release
CCACHE_VERSION: 3.7.7

jobs:
build:
name: ${{ matrix.config.name }}
runs-on: ${{ matrix.config.os }}
strategy:
fail-fast: false
matrix:
config:
- {
name: "Ubuntu Latest GCC",
artifact: "Linux.7z",
os: ubuntu-latest,
cc: "gcc",
cxx: "g++",
}

steps:
  - uses: actions/checkout@v1

  - name: Test bash
    shell: bash
    run: |
      echo Using host CMake version: ${CMAKE_VERSION}

  - name: Test cmake
    shell: cmake -P {0}
    run: |
      message(STATUS "hello from cmake script")

Executing the above results in the following error:

$ ~/prgs/nektos/forks/act/act
[CMake Build Matrix/Ubuntu Latest GCC] 🧪 Matrix: map[config:map[artifact:Linux.7z cc:gcc cxx:g++ name:Ubuntu Latest GCC os:ubuntu-latest]]
[CMake Build Matrix/Ubuntu Latest GCC] 🚀 Start image=ubuntu-with-hello
[CMake Build Matrix/Ubuntu Latest GCC] 🐳 docker run image=ubuntu-with-hello entrypoint=["/usr/bin/tail" "-f" "/dev/null"] cmd=[]
[CMake Build Matrix/Ubuntu Latest GCC] 🐳 docker cp src=/home/wink/prgs/cmake/projects/gha-cmake-HelloWorld/. dst=/github/workspace
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run actions/checkout@v1
[CMake Build Matrix/Ubuntu Latest GCC] ✅ Success - actions/checkout@v1
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run Test bash
| Using host CMake version: 3.18.3
[CMake Build Matrix/Ubuntu Latest GCC] ✅ Success - Test bash
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run Test cmake
| CMake Error at /github/workflow/2:1:
| Parse error. Expected a command name, got unquoted argument with text
| "PATH=":${PATH}"".
|
|
| CMake Error: Error processing file: /github/workflow/2
[CMake Build Matrix/Ubuntu Latest GCC] ❌ Failure - Test cmake
Error: exit with FAILURE: 1

With this change the output is:

$ ~/prgs/nektos/forks/act/act
[CMake Build Matrix/Ubuntu Latest GCC] 🧪 Matrix: map[config:map[artifact:Linux.7z cc:gcc cxx:g++ name:Ubuntu Latest GCC os:ubuntu-latest]]
[CMake Build Matrix/Ubuntu Latest GCC] 🚀 Start image=ubuntu-with-hello
[CMake Build Matrix/Ubuntu Latest GCC] 🐳 docker run image=ubuntu-with-hello entrypoint=["/usr/bin/tail" "-f" "/dev/null"] cmd=[]
[CMake Build Matrix/Ubuntu Latest GCC] 🐳 docker cp src=/home/wink/prgs/cmake/projects/gha-cmake-HelloWorld/. dst=/github/workspace
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run actions/checkout@v1
[CMake Build Matrix/Ubuntu Latest GCC] ✅ Success - actions/checkout@v1
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run Test bash
| Using host CMake version: 3.18.3
[CMake Build Matrix/Ubuntu Latest GCC] ✅ Success - Test bash
[CMake Build Matrix/Ubuntu Latest GCC] ⭐ Run Test cmake
| -- hello from cmake script
[CMake Build Matrix/Ubuntu Latest GCC] ✅ Success - Test cmake

[cplee]

thanks @winksaville - couple thoughts:

• rather than explicitly skipping the PATH for cmake, can we change it to ONLY add path for a list of supported shells?
• can you include a test case for this?

[winksaville]

Closing this as I think PR #406 is better, but can resurrect this if this is the way you'd like to go.