CI/CD: CI_PROJECT_DIR variable uses wrong/invalid path separator character in GitLab Runner for Windows
### Summary
GitLab CI/CD variables containing file paths are forwarded to scripts contained in `.gitlab-ci.yml` script sections as-is.
However, for **GitLab Runner for Windows**, the variable values' path separator character must be changed in all the variable values from "`/`" to "`\`" before being forwarded to *GitLab Runner for Windows*. Otherwise, *GitLab Runner for Windows* execution fails.
### Steps to reproduce
```yaml
after_script:
- XCOPY "C:\Some\Output\*.xml" "%CI_PROJECT_DIR%\xUnit-Reports\" /Y /I
```
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### What is the current *bug* behavior?
Scripts executed by **GitLab Runner for Windows** fail due to incorrect file path separator characters in **GitLab CI/CD** variable values.
<br/>
### What is the expected *correct* behavior?
**GitLab CI/CD** should replace all "`/`" characters in *GitLab CI/CD* variable values containing paths with the "`\`" character for all variables forwarded to **GitLab Runner for Windows**.
issue