Change PowerShell from 'master' to 'main' branch

Author: fleschutz

data/popular-repositories.csv

@@ -17,7 +17,7 @@ ninja,             "build tool",         "https://github.com/ninja-build/ninja",
 opencv,            "dev lib",            "https://github.com/opencv/opencv",               master,  yes, 
 operating-systems, "OS collection",      "git@github.com:fleschutz/operating-systems.git", main,    yes,
 papers,            "collection",         "git@github.com:fleschutz/papers.git",            main,    yes,
-PowerShell,        "script collection",  "git@github.com:fleschutz/PowerShell.git",        master,  yes,
+PowerShell,        "script collection",  "git@github.com:fleschutz/PowerShell.git",        main,    yes,
 pwsh,              "shell",              "https://github.com/PowerShell/PowerShell",       master,  yes,
 protobuf,          "dev lib",            "https://github.com/protocolbuffers/protobuf",    main,    yes,
 rust,              "compiler",           "https://github.com/rust-lang/rust",              master,  yes,