ci(contracts): run workflows on prs

Author: piotr-roslaniec

.github/workflows/contracts-ecdsa.yml

@@ -1,6 +1,9 @@
 name: Solidity ECDSA
 
 on:
+  pull_request:
+    branches:
+      - main
   # We intend to use `workflow dispatch` in two different situations/paths:
   # 1. If a workflow will be manually dispatched from branch named
   #    `dapp-development`, workflow will deploy the contracts on the selected

.github/workflows/contracts-random-beacon.yml

@@ -1,6 +1,9 @@
 name: Solidity Random Beacon
 
 on:
+  pull_request:
+    branches:
+      - main
   # We intend to use `workflow dispatch` in two different situations/paths:
   # 1. If a workflow will be manually dispatched from branch named
   #    `dapp-development`, workflow will deploy the contracts on the selected