Add plugin for SDKMAN (#6483)

plugins/sdk/README.md

+# sdk
+
+Plugin for SDKMAN, a tool for managing parallel versions of multiple Software Development Kits on most Unix based systems.
+Provides autocompletion for all known commands.
+
+## Requirements
+
+ * [SDKMAN](http://sdkman.io/)

plugins/sdk/sdk.plugin.zsh

+### SDKMAN Autocomplete for Oh My Zsh
+
+# This is the output from sdkman. All the these options are supported at the
+# moment.
+
+# Usage: sdk <command> [candidate] [version]
+#        sdk offline <enable|disable>
+#
+#    commands:
+#        install   or i    <candidate> [version]
+#        uninstall or rm   <candidate> <version>
+#        list      or ls   [candidate]
+#        use       or u    <candidate> [version]
+#        default   or d    <candidate> [version]
+#        current   or c    [candidate]
+#        upgrade   or ug   [candidate]
+#        version   or v
+#        broadcast or b
+#        help      or h
+#        offline           [enable|disable]
+#        selfupdate        [force]
+#        update
+#        flush             <candidates|broadcast|archives|temp>
+#
+#    candidate  :  the SDK to install: groovy, scala, grails, gradle, kotlin, etc.
+#                  use list command for comprehensive list of candidates
+#                  eg: $ sdk list
+#
+#    version    :  where optional, defaults to latest stable if not provided
+#                  eg: $ sdk install groovy
+
+local _sdk_commands=(
+    install     i
+    uninstall   rm
+    list        ls
+    use         u
+    default     d
+    current     c
+    upgrade     ug
+    version     v
+    broadcast   b
+    help        h
+    offline
+    selfupdate
+    update
+    flush
+)
+
+_listInstalledVersions() {
+  __sdkman_build_version_csv $1 | sed -e "s/,/ /g"
+}
+
+_listInstallableVersions() {
+  __sdkman_list_versions $1 | grep "^ " | sed -e "s/\* /*/g" | \
+      sed -e "s/>//g" | xargs -n 1 echo | grep -v "^*"
+}
+
+_listAllVersion() {
+  __sdkman_list_versions $1 | grep "^ " | sed -e "s/\*/ /g" | sed -e "s/>//g"
+}
+
+_sdk () {
+  case $CURRENT in
+    2)  compadd -- $_sdk_commands ;;
+    3)  case "$words[2]" in
+          i|install|rm|uninstall|ls|list|u|use|d|default|c|current|ug|upgrade)
+                      compadd -- $SDKMAN_CANDIDATES ;;
+          offline)    compadd -- enable disable ;;
+          selfupdate) compadd -- force ;;
+          flush)      compadd -- candidates broadcast archives temp ;;
+        esac
+        ;;
+    4)  case "$words[2]" in
+          rm|uninstall|d|default) compadd -- $(_listInstalledVersions $words[3]) ;;
+          i|install)              compadd -- $(_listInstallableVersions $words[3]) ;;
+          u|use)                  compadd -- $(_listAllVersion $words[3]) ;;
+        esac
+        ;;
+  esac
+}
+
+compdef _sdk sdk