fix(prepare): add await to call of normalizeVersion

Author: abichinger

lib/prepare.js

@@ -45,7 +45,7 @@ async function bDistPackage(setupPy, distDir){
 async function prepare(pluginConfig, { nextRelease }){
     let setupPy = getOption(pluginConfig, 'setupPy')
     let distDir = getOption(pluginConfig, 'distDir')
-    let version = normalizeVersion(nextRelease.version)
+    let version = await normalizeVersion(nextRelease.version)
 
     await setReleaseVersion(setupPy, version)
     await sDistPackage(setupPy, distDir)