fix ci failed to download. (sofastack#700)

* upgrade http protocol to https.

* fix download forbidden.

* accelerate integration test builds.

* accelerate integration test builds.

* add .codecov.yml

* adjust codecov threshold.

* add maven install -U parameter.

.codecov.yml

@@ -0,0 +1,6 @@
+coverage:
+  status:
+    project:
+      default:
+        threshold: 0.1%
+    patch: off

.travis.yml

@@ -6,13 +6,16 @@ dist: trusty
 jdk:
   - oraclejdk8
 
+cache:
+  directories:
+    - $HOME/.m2
+
 before_install:
   - echo "Downloading Maven 3.2.5"
     && wget https://archive.apache.org/dist/maven/maven-3/3.2.5/binaries/apache-maven-3.2.5-bin.zip
     && unzip -q apache-maven-3.2.5-bin.zip
     && export M2_HOME=$PWD/apache-maven-3.2.5
     && export PATH=$M2_HOME/bin:$PATH
-    && cp ./tools/ci/.travis.settings.xml $HOME/.m2/settings.xml
     && mvn -version
 
 install:

pom.xml

@@ -269,7 +269,7 @@
             <id>ci-install</id>
             <properties>
                 <skipTests>true</skipTests>
-                <maven.javadoc.skip>false</maven.javadoc.skip>
+                <maven.javadoc.skip>true</maven.javadoc.skip>
                 <module.jacoco.skip>true</module.jacoco.skip>
             </properties>
         </profile>