chore(java): remove pin on Apache Maven 3.8.1 from github actions (#1268)

* chore(java): remove pin on Apache Maven 3.8.1 from github actions 

[Ubuntu 20.04.3 LTS](https://github.com/actions/virtual-environments/blob/main/images/linux/Ubuntu2004-README.md) has updated the maven version to 3.8.3 which resolves[ the issue](#1202) maven 3.8.2 had with flatten-maven-plugin

* chore: fix tests

Author: Neenu1995

synthtool/gcp/templates/java_library/.github/workflows/ci.yaml

@@ -12,9 +12,6 @@ jobs:
         java: [8, 11, 17]
     steps:
     - uses: actions/checkout@v2
-    - uses: stCarolas/setup-maven@v4
-      with:
-        maven-version: 3.8.1
     - uses: actions/setup-java@v2
       with:
         distribution: zulu
@@ -27,9 +24,6 @@ jobs:
     runs-on: windows-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: stCarolas/setup-maven@v4
-      with:
-        maven-version: 3.8.1
     - uses: actions/setup-java@v2
       with:
         distribution: zulu
@@ -45,9 +39,6 @@ jobs:
         java: [8, 11, 17]
     steps:
     - uses: actions/checkout@v2
-    - uses: stCarolas/setup-maven@v4
-      with:
-        maven-version: 3.8.1
     - uses: actions/setup-java@v2
       with:
         distribution: zulu
@@ -58,9 +49,6 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: stCarolas/setup-maven@v4
-      with:
-        maven-version: 3.8.1
     - uses: actions/setup-java@v2
       with:
         distribution: zulu
@@ -73,14 +61,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
-    - uses: stCarolas/setup-maven@v4
-      with:
-        maven-version: 3.8.1
     - uses: actions/setup-java@v2
       with:
         distribution: zulu
         java-version: 8
     - run: java -version
     - run: .kokoro/build.sh
       env:
-        JOB_TYPE: clirr
+        JOB_TYPE: clirr