Bump xu-cheng/latex-action from 3 to 4

Bumps [xu-cheng/latex-action](https://github.com/xu-cheng/latex-action) from 3 to 4.
- [Release notes](https://github.com/xu-cheng/latex-action/releases)
- [Commits](xu-cheng/latex-action@v3...v4)

---
updated-dependencies:
- dependency-name: xu-cheng/latex-action
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/build_latex.yml

@@ -8,7 +8,7 @@ jobs:
       uses: actions/checkout@v4
 
     - name: Build LaTeX files
-      uses: xu-cheng/latex-action@v3
+      uses: xu-cheng/latex-action@v4
       with:
         root_file: thesis.tex
         latexmk_use_lualatex: true