Simplify ignored file list

Author: dfed

.gitignore

@@ -1,25 +1,4 @@
 # Xcode
 .DS_Store
-build/
+.swiftpm
 .build/
-*.pbxuser
-!default.pbxuser
-*.mode1v3
-!default.mode1v3
-*.mode2v3
-!default.mode2v3
-*.perspectivev3
-!default.perspectivev3
-*.xcworkspace
-!default.xcworkspace
-*xcuserdata
-profile
-*.moved-aside
-DerivedData
-.idea/
-.swiftpm/
-generated/
-*coverage.txt
-
-# We can generate Xcode projects from the Swift packages.
-*.xcodeproj/