Change maven version in workflows

Author: jvalkeal

.github/workflows/next-dev-version.yml

@@ -13,7 +13,7 @@ jobs:
         java-version: 1.8
     - uses: jvalkeal/setup-maven@v1
       with:
-        maven-version: 3.6.3
+        maven-version: 3.8.4
     - uses: jfrog/setup-jfrog-cli@v1
       with:
         version: 1.46.4

.github/workflows/release-milestone.yml

@@ -19,7 +19,7 @@ jobs:
         java-version: 1.8
     - uses: jvalkeal/setup-maven@v1
       with:
-        maven-version: 3.6.3
+        maven-version: 3.8.4
     - uses: jfrog/setup-jfrog-cli@v1
       with:
         version: 1.46.4