Update README.md to reflect latest version (#196)

Author: npwolf

README.md

@@ -36,8 +36,8 @@ jobs:
         ...
         steps:
             - uses: actions/checkout@v3
-            # Make sure the @v0.7.0 matches the current version of the action
-            - uses: webfactory/ssh-agent@v0.7.0
+            # Make sure the @v0.8.0 matches the current version of the action
+            - uses: webfactory/ssh-agent@v0.8.0
               with:
                   ssh-private-key: ${{ secrets.SSH_PRIVATE_KEY }}
             # ... other steps
@@ -52,7 +52,7 @@ You can set up different keys as different secrets and pass them all to the acti
 
 ```yaml
 # ... contents as before
-            - uses: webfactory/ssh-agent@v0.7.0
+            - uses: webfactory/ssh-agent@v0.8.0
               with:
                   ssh-private-key: |
                         ${{ secrets.FIRST_KEY }}