fix `planet/version'

Closes PR 13975

pkgs/planet-lib/planet/private/version.rkt

@@ -4,6 +4,7 @@
          racket/match
          unstable/syntax
          racket/syntax
+         racket/private/this-expression-source-directory
          planet/planet-archives)
 
 (provide this-package-version

pkgs/racket-pkgs/racket-test/tests/planet/examples/dummy-package/me.rkt

@@ -0,0 +1,4 @@
+#lang racket/base
+(require planet/version)
+(provide me)
+(define me (this-package-version))

pkgs/racket-pkgs/racket-test/tests/planet/lang.rkt

@@ -15,6 +15,8 @@
  => (void)
  (dynamic-require `(file ,(in-here "examples/dummy-module.rkt")) 'result)
  => '(successful test result)
+ (dynamic-require '(planet plt/dummy-package/me) 'me)
+ => '("plt" "dummy-package.plt" 1 0)
  (remove-hard-link "plt" "dummy-package.plt" 1 0)
  => (void)