Auto merge of #22569 - IlyaBizyaev:add-opensuse-depends, r=ferjm

Add missing build dependencies for openSUSE

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GStreamer development packages and Autotools 2.13 are required for a successful build of servo on openSUSE Linux.
This commit adds missing dependencies (compare with e.g. Fedora and Arch).

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

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because they only affect documentation

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README.md

@@ -178,7 +178,8 @@ export LIBCLANG_PATH=/opt/rh/llvm-toolset-7/root/usr/lib64
 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 glu-devel ccache llvm-clang libclang
+    python-pip python-virtualenv rpm-build glu-devel ccache llvm-clang libclang autoconf213 gstreamer-devel \
+    gstreamer-plugins-base-devel gstreamer-plugins-bad-devel
 ```
 #### On Arch Linux