Update the swiftpm plugin autocompletion for Swift 5.0

plugins/swiftpm/README.md

@@ -20,3 +20,22 @@ plugins=(... swiftpm)
 | `spx` | Generates an Xcode project          | `swift package generate-xcodeproj` |
 | `sps` | Print the resolved dependency graph | `swift package show-dependencies`  |
 | `spd` | Print parsed Package.swift as JSON  | `swift package dump-package`       |
+
+## Autocompletion
+
+The `_swift` file enables autocompletion for Swift Package Manager. Current version supports Swift 5.0
+
+
+### Updating the autocompletion for new version of Swift
+
+To update autocompletion to the Swift version present on your system:
+```
+swift package completion-tool generate-zsh-script > ~/.oh-my-zsh/plugins/swiftpm/_swift
+```
+
+### Known issues
+
+If `swiftpm` is not added to your zsh plugins list, autocompletion will still be triggered but will result in errors:
+```
+_values:compvalues:10: not enough arguments
+```