Update .gitignore

Fix for some request to change. See #247 (comment)

.gitignore

@@ -206,7 +206,7 @@ playground.xcworkspace
 # *.xcodeproj
 # Xcode automatically generates this directory with a .xcworkspacedata file and xcuserdata
 # hence it is not needed unless you have added a package configuration file to your project
-# .swiftpm
+.swiftpm
 
 .build/
 
@@ -274,4 +274,18 @@ $RECYCLE.BIN/
 # Windows shortcuts
 *.lnk
 
-# End of https://www.toptal.com/developers/gitignore/api/macos,windows,linux,swift,swiftpackagemanager,swiftpm,cocoapods,carthage,objective-c,ruby
+# End of https://www.toptal.com/developers/gitignore/api/macos,windows,linux,swift,swiftpackagemanager,swiftpm,cocoapods,carthage,objective-c,ruby
+
+# Added manually.
+# See https://github.com/ephread/Instructions/pull/247#issuecomment-708517304
+## Build generated
+Tests
+
+## Other
+*.xcuserstate
+
+## Carthage
+**/Carthage/Checkouts
+**/Carthage/Build
+
+Skassets