Fix ci/show_versions.jl

Author: tkf

ci/show_versions.jl

@@ -1,4 +1,10 @@
-for line in split(strip(readstring("REQUIRE")), '\n')[2:end]
-    name = split(line)[1]
-    println(name, "\t", Pkg.installed(name))
+if VERSION >= v"0.7.0-"
+    using Pkg
+    show(stdout, "text/plain", Pkg.installed())
+    println()
+else
+    for line in split(strip(readstring("REQUIRE")), '\n')[2:end]
+        name = split(line)[1]
+        println(name, "\t", Pkg.installed(name))
+    end
 end