Merge pull request #10 from DeLaGuardo/notes-about-gu-using

Add a note about how to use gu binary + add 21.0.0

.github/workflows/self_check.yml

@@ -9,7 +9,8 @@ jobs:
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
         binary: [java, java.exe]
-        graalvm-version: [19.3.0.java8, 19.3.0.java11, 20.0.0.java8, 20.0.0.java11, 20.1.0.java8, 20.1.0.java11, 20.2.0.java8, 20.2.0.java11]
+        gu-binary: [gu, gu.cmd]
+        graalvm-version: [19.3.0.java8, 19.3.0.java11, 20.0.0.java8, 20.0.0.java11, 20.1.0.java8, 20.1.0.java11, 20.2.0.java8, 20.2.0.java11, 20.3.0.java8, 20.3.0.java11, 20.3.1.java8, 20.3.1.java11, 21.0.0.java8, 21.0.0.java11]
         exclude:
           - os: ubuntu-latest
             binary: java.exe

README.md

@@ -21,6 +21,37 @@ steps:
 - run: java -version
 ```
 
+# Using GraalVM Component Updater (aka. gu)
+
+`gu` binary is available as `gu` on ubuntu and macos, on windows - as `gu.cmd`.
+
+``` yaml
+jobs:
+  sample-job:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+        gu-binary: [gu, gu.cmd]
+        exclude:
+          - os: ubuntu-latest
+            gu-binary: gu.cmd
+          - os: macos-latest
+            gu-binary: gu.cmd
+          - os: windows-latest
+            gu-binary: gu
+    steps:
+      - name: Setup Graalvm
+        id: setup-graalvm
+        uses: DeLaGuardo/setup-graalvm@master
+        with:
+          graalvm-version: '21.0.0.java11'
+
+      - name: Install native-image component
+        run: |
+          ${{ matrix.gu-binary }} install native-image
+```
+
 # License
 
 The scripts and documentation in this project are released under the [MIT License](LICENSE)