add workflow for chaining jobs in github actions

.github/context-and-variables.md

@@ -113,4 +113,8 @@ When accessing a variable, the lookup follows this order:
 Hence, in the above example, the output is as follows:
 
 ```bash
+value of VAR1 is myworkflowvar1
+value of VAR1 is myworkflowvar1
+value of VAR2 is myjobvar2
+value of VAR3 is mystepvar3
 ``` 

.github/workflows/chainingJobs.yml

@@ -0,0 +1,48 @@
+name: Chaining Jobs
+
+on:
+  workflow_dispatch:
+
+    inputs:
+      run-job-3:
+        description: "Run job 3"
+        type: boolean
+
+jobs:
+
+  job-1:
+    name: Job 1  
+    runs-on: ubuntu-latest
+    steps:
+    - name: Output for Job 1
+      run: echo "Hello from Job 1. Run Job 3 equals ${{ github.event.inputs.run-job-3 }}" 
+
+  job-2:
+    name: Job 2
+    runs-on: ubuntu-latest
+    needs:
+      - job-1
+    steps:
+    - name: Output for Job 2
+      run: echo "Hello from Job 2"
+
+  job-3:
+    name: Job 3
+    if: github.event.inputs.run-job-3 == 'true' # if the input is false, this job would be skipped
+    runs-on: ubuntu-latest
+    needs:
+      - job-1
+    steps:
+    - name: Output for Job 3
+      run: echo "Hello from Job 3"
+
+  job-4:
+    name: Job 4
+    runs-on: ubuntu-latest
+    # if: always()    # Causes the job to always execute
+    needs:    
+      - job-2
+      - job-3
+    steps:
+    - name: Output for Job 4
+      run: echo "Hello from Job 4"