servo: Merge #13545 - Update README.md to include glu-devel for openS…

…USE dependencies (from j-koreth:master); r=KiChjang

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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [X] These changes fix #13542 (github issue number if applicable).

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- [X] These changes do not require tests because only updating README.md

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My apologies, on my machine I had glu-devel installed previously for another project and didn't realize this also needed it.

Source-Repo: https://github.com/servo/servo
Source-Revision: ce79e0464487ff640d7c1d0f58f74ef28c36b481

servo/README.md

@@ -76,7 +76,7 @@ sudo dnf install curl freeglut-devel libtool gcc-c++ libXi-devel \
 sudo zypper install libX11-devel libexpat-devel libbz2-devel Mesa-libEGL-devel Mesa-libGL-devel cabextract cmake \
     dbus-1-devel fontconfig-devel freetype-devel gcc-c++ git glib2-devel gperf \
     harfbuzz-devel libOSMesa-devel libXcursor-devel libXi-devel libXmu-devel libXrandr-devel libopenssl-devel \
-    python-pip python-virtualenv rpm-build
+    python-pip python-virtualenv rpm-build glu-devel
 ```
 #### On Arch Linux