Update .gitlinks

Author: chronoxor

.gitlinks

@@ -1,6 +1,6 @@
 # Modules
 Catch2 modules/Catch2 https://github.com/catchorg/Catch2.git devel
-cpp-optparse modules/cpp-optparse https://github.com/weisslj/cpp-optparse.git master
+cpp-optparse modules/cpp-optparse https://github.com/weisslj/cpp-optparse.git main
 HdrHistogram modules/HdrHistogram https://github.com/HdrHistogram/HdrHistogram_c.git main
 zlib modules/zlib https://github.com/madler/zlib.git master