Trim plugin version string (#890)

Duplicate of https://github.com/rojo-rbx/rojo/pull/889, but based on
master as per request.

This PR is a very small change that fixes the string pattern that reads
the rojo version from `Version.txt`. Currently this reads an extra
new-line character which makes reading the version text in the plugin
difficult.

It seems the rust side of things already trims the string when
comparing, but the lua side does not.

plugin/src/Config.lua

@@ -3,7 +3,8 @@ local strict = require(script.Parent.strict)
 local isDevBuild = script.Parent.Parent:FindFirstChild("ROJO_DEV_BUILD") ~= nil
 
 local Version = script.Parent.Parent.Version
-local major, minor, patch, metadata = Version.Value:match("^(%d+)%.(%d+)%.(%d+)(.*)$")
+local trimmedVersionValue = Version.Value:gsub("^%s+", ""):gsub("%s+$", "")
+local major, minor, patch, metadata = trimmedVersionValue:match("^(%d+)%.(%d+)%.(%d+)(.*)$")
 
 local realVersion = { major, minor, patch, metadata }
 for i = 1, 3 do