docs: fix plugin example (export verifyConditions, not verify) (#2192)

plugin example was exporting `verify`, not `verifyConditions`

docs/developer-guide/plugin.md

@@ -34,7 +34,7 @@ We recommend you setup a linting system to ensure good javascript practices are
 In your `index.js` file, you can start by writing the following code
 
 ```javascript
-const verifyConditions = require('./src/verify');
+const verify = require('./src/verify');
 
 let verified;
 
@@ -43,12 +43,12 @@ let verified;
  * @param {*} pluginConfig The semantic-release plugin config
  * @param {*} context The context provided by semantic-release
  */
-async function verify(pluginConfig, context) {
-  await verifyConditions(pluginConfig, context);
+async function verifyConditions(pluginConfig, context) {
+  await verify(pluginConfig, context);
   verified = true;
 }
 
-module.exports = { verify };
+module.exports = { verifyConditions };
 ```
 
 Then, in your `src` folder, create a file called `verify.js` and add the following