From 9beb2ed44e3b7ad3eeaf6710b2195e50ac39016f Mon Sep 17 00:00:00 2001
From: Simon Zeltser <zeltser@google.com>
Date: Wed, 8 Sep 2021 16:12:44 -0700
Subject: [PATCH] fix: update CI to use maven 3.8.1 (#662)

Gitbub Action updated LTS(18.04, 20.04) versions of Github-Hosted runners for Ubuntu with the latest version of Apache Maven. The new version of Ubuntu has Apache Maven 3.8.2 which is incompatible with flatten-maven-plugin:1.2.7. This caused all github actions using the latest Ubuntu version to fail with this error.

The immediate solution is to use this community action to install maven 3.8.1 at runtime.
---
 .github/workflows/ci.yaml | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 65ae6ecdd..36233e72d 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -11,6 +11,9 @@ jobs:
       matrix:
         java: [8, 11]
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
@@ -22,6 +25,9 @@ jobs:
   windows:
     runs-on: windows-latest
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
@@ -36,6 +42,9 @@ jobs:
       matrix:
         java: [8, 11]
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
@@ -45,6 +54,9 @@ jobs:
   linkage-monitor:
     runs-on: ubuntu-latest
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
@@ -58,6 +70,9 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with:
@@ -69,6 +84,9 @@ jobs:
   clirr:
     runs-on: ubuntu-latest
     steps:
+    - uses: stCarolas/setup-maven@v4
+      with:
+        maven-version: 3.8.1
     - uses: actions/checkout@v2
     - uses: actions/setup-java@v1
       with: