[DW-31] Add a condition that prohibits checks to be run on draft PRs

Unfortunately, github actions doesn't support using "if" property in
defaults and that's why we need to repeat it for all jobs

.github/workflows/main.yml

@@ -1,10 +1,17 @@
 name: CI
 
-on: [pull_request]
+on:
+  pull_request:
+    types:
+      - opened
+      - synchronize
+      - reopened
+      - ready_for_review
 
 jobs:
   check_commit_messages:
     name: check commit messages
+    if: github.event.pull_request.draft == false
     runs-on: self-hosted
     steps:
       - name: clone repository
@@ -14,12 +21,14 @@ jobs:
       - name: check commit messages
         run: ./tools/check_commit_messages.py
   build:
+    if: github.event.pull_request.draft == false
     runs-on: self-hosted
     steps:
       - name: build
         run: echo "Placeholder for old CI scripts"
   check_copyright_and_style:
     name: check copyright and style
+    if: github.event.pull_request.draft == false
     runs-on: self-hosted
     steps:
       - name: clone repository
@@ -35,6 +44,7 @@ jobs:
 
   build_rt1051_binary:
     name: build rt1051 binary
+    if: github.event.pull_request.draft == false
     needs:
       - check_copyright_and_style
     runs-on: self-hosted
@@ -56,6 +66,7 @@ jobs:
 
   build_linux_binary_and_run_tests:
     name: build linux binary and run tests
+    if: github.event.pull_request.draft == false
     needs:
       - check_copyright_and_style
     runs-on: self-hosted