Simplification and modification of features (#8)

* Default token, instead of requirement.
* README cleanup
* Update to node20

Author: s1204IT

README.md

@@ -1,33 +1,37 @@
 Unlock an issue. By default, it uses the context's but can be targetted.
 
 ### Targetting context's issue:
-
-    - uses: OSDKDev/unlock-issues@v1.1
-      with:
-        repo-token: "${{ secrets.GITHUB_TOKEN }}"
-        
+```yml
+- name: Unlock issue
+  uses: OSDKDev/unlock-issues@v1.2
+```  
 #### Sample file: `.github/workflows/unlock-reopened-issues.yml`
-    name: Unlock reopened issue
+```yml
+name: Unlock reopened issue
 
-    on: 
-      issues:
-        types: [reopened]
+on:
+  issues:
+    types: [reopened]
 
-    jobs:
-      lock:
-        runs-on: ubuntu-latest
-        steps:
-        - uses: OSDKDev/unlock-issues@v1.1
-          with:
-            repo-token: "${{ secrets.GITHUB_TOKEN }}"
-        
+jobs:
+  unlock:
+    name: Unlock
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+    steps:
+    - name: Unlock issue
+      uses: OSDKDev/unlock-issues@v1.2
+```
 As simple as that!
 
 ### Targetting a specific issue / repo:
-
-    - uses: OSDKDev/unlock-issues@v1.1
+```yml
+    - name: Unlock issue
+      uses: OSDKDev/unlock-issues@v1.2
       with:
         repo-token: {Token with permissions over the target repository / issue}
         owner-name: {Owner Name - Optional - Default: Context's Repository Owner}
         repo-name: {Repository Name - Optional - Default: Context's Repository}
         issue-number: {Issue Number - Optional - Default: Context's Issue}
+```

action.yml

@@ -4,6 +4,7 @@ inputs:
   repo-token:
     description: 'Token for the repo. Can be passed in using {{ secrets.GITHUB_TOKEN }}'
     required: true
+    default: '${{ github.token }}'
   issue-number:
     description: "Issue number. Defaults to context's issue"
     required: false
@@ -17,5 +18,5 @@ branding:
   icon: unlock
   color: black
 runs:
-  using: 'node12'
+  using: 'node20'
   main: 'src/unlock.js'