Update GitHub actions matching latest Java requirements

.github/workflows/build.yml

@@ -6,17 +6,16 @@ jobs:
   build:
     strategy:
       matrix:
-        java: ["8", "11"]
         os: ["ubuntu-latest"]
     runs-on: "${{ matrix.os }}"
     steps:
     - name: "Checkout Repository"
       uses: "actions/checkout@v2.3.4"
-    - name: "Setup JDK ${{ matrix.java }}"
+    - name: "Setup JDK 11"
       uses: "actions/setup-java@v2"
       with:
           distribution: "adopt"
-          java-version: "${{ matrix.java }}"
+          java-version: "11"
     - name: "Cache Gradle"
       uses: "actions/cache@v2.1.4"
       with:
@@ -30,9 +29,9 @@ jobs:
       uses: "actions/cache@v2.1.4"
       with:
         path: "~/.m2/repository"
-        key: "${{ runner.os }}-${{ matrix.java }}-maven-${{ hashFiles('**/pom.xml') }}"
+        key: "${{ runner.os }}-11-maven-${{ hashFiles('**/pom.xml') }}"
         restore-keys: |
-          "${{ runner.os }}-${{ matrix.java }}-maven-"
+          "${{ runner.os }}-11-maven-"
     - name: "Cache BuildTools Decompiled Code"
       uses: "actions/cache@v2.1.4"
       with:
@@ -40,7 +39,7 @@ jobs:
         key: "${{ runner.os }}-buildtools"
         restore-keys: |
           "${{ runner.os }}-buildtools"
-    - name: "Test Enviornment"
+    - name: "Test Environment"
       run: "echo $GITHUB_WORKSPACE"
     - name: "Download BuildTools"
       run: "wget https://hub.spigotmc.org/jenkins/job/BuildTools/lastSuccessfulBuild/artifact/target/BuildTools.jar"
@@ -54,5 +53,3 @@ jobs:
       run: |
         rm -f ~/.gradle/caches/modules-2/modules-2.lock
         rm -f ~/.gradle/caches/modules-2/gc.properties
-
-