Fix semaphore

src/upgrader.ts

@@ -185,7 +185,11 @@ export abstract class Upgrader {
     }
 
     private async protectedDeployNewImplementation (contract: string) {
-        await this.deploySemaphore.acquire();
+        // Iterations have to be sequential
+        // eslint-disable-next-line no-await-in-loop
+        while(!await this.deploySemaphore.acquire()) {
+            console.log(`Deployment of the ${contract} implementation is waiting`);
+        }
         let result: ContractToUpgrade | null = null;
         try {
             result = await this.deployNewImplementation(contract);