Repository: JsonMapper/JsonMapper (php)

Issue:
PHP 8.0 is allowed to fail
**Describe the bug**
In the build chain PHP 8.0 (Nightly) is still allowed to fail.

**To Reproduce**
Steps to reproduce the behavior:
See the build report where Nightly is allowed to fail.

**Expected behavior**
A breaking test in PHP 8.0 should fail the build. The Nightly (target PHP 8.1) is still allowed to fail.

**Stacktrace**
N/A

**Environment (please complete the following information):**
 - PHP: 8.0
 
**Additional context**
N/A


Pull request description:
Update build chain
This PR would fix #69 

Patch:
diff --git a/.travis.yml b/.travis.yml
index 6064111..c2c5b0c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -16,6 +16,9 @@ matrix:
     - php: 7.4
     - php: 7.4
       env: COMPOSER_UPDATE_FLAGS='--prefer-lowest --prefer-stable'
+    - php: 8.0
+    - php: 8.0
+      env: COMPOSER_UPDATE_FLAGS='--prefer-lowest --prefer-stable'
 
       # Ignore the platform requirements for the upcoming PHP version
     - php: nightly
@@ -33,7 +36,6 @@ branches:
   only:
     - master
     - develop
-    - 2.x
 
 install:
   - curl -s http://getcomposer.org/installer | php
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b1d68f9..18f71e5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Added
 - Support variadic setter function. [PR#68](https://github.com/JsonMapper/JsonMapper/pull/68)
+### Fixed
+- Include PHP 8.0 in the build matrix. [PR#70](https://github.com/JsonMapper/JsonMapper/pull/70)
 
 ## [2.0.0] - 2021-01-07
 ### Changed


Test patch:
diff --git a/.github/workflows/run-tests.yaml b/.github/workflows/run-tests.yaml
index 517d773..8b2d31b 100644
--- a/.github/workflows/run-tests.yaml
+++ b/.github/workflows/run-tests.yaml
@@ -2,9 +2,9 @@ name: Run tests
 
 on:
   push:
-    branches: [ develop, master, 2.0.0-dev ]
+    branches: [ develop, master ]
   pull_request:
-    branches: [ develop, master, 2.x ]
+    branches: [ develop, master ]
 
 jobs:
   build:
@@ -34,14 +34,23 @@ jobs:
             composer_update_flags: '--prefer-lowest --prefer-stable'
             name: 'PHP 7.4 with lowest stable deps'
           - php: 8.0
-            allow_fail: true
+            allow_fail: false
             php_ini: 'xdebug.coverage_enable=On'
             name: 'PHP 8.0 with latest deps'
           - php: 8.0
-            allow_fail: true
+            allow_fail: false
             composer_update_flags: '--prefer-lowest --prefer-stable'
             php_ini: 'xdebug.coverage_enable=On'
             name: 'PHP 8.0 with lowest stable deps'
+          - php: 8.1
+            allow_fail: true
+            php_ini: 'xdebug.coverage_enable=On'
+            name: 'PHP 8.1 with latest deps'
+          - php: 8.1
+            allow_fail: true
+            composer_update_flags: '--prefer-lowest --prefer-stable'
+            php_ini: 'xdebug.coverage_enable=On'
+            name: 'PHP 8.1 with lowest stable deps'
 
     runs-on: ubuntu-latest