We should use go 1.14.4 to build mender-artifact

mender.xml

@@ -24,7 +24,7 @@
   <exec executable="./make.bash" dir="${makedir}/src"/>
   <move file="${builddir}/go" tofile="${builddir}/go1.4"/>
   <exec executable="tar" failonerror="true">
-   <arg line="xf ${basedir}/build-system/packages/go/go1.12.6.src.tar.gz -C ${builddir}"/>
+   <arg line="xf ${basedir}/build-system/packages/go/go1.14.4.src.tar.gz -C ${builddir}"/>
   </exec>
   <exec executable="./make.bash" dir="${makedir}/src">
    <env key="GOROOT_BOOTSTRAP" path="${builddir}/go1.4"/>
@@ -42,6 +42,12 @@
   <exec executable="mv" dir="${builddir}" failonerror="true">
    <arg line="${builddir}/go/src/github.com/mendersoftware/mender-artifact-3.3.0 ${builddir}/go/src/github.com/mendersoftware/mender-artifact"/>
   </exec>
+  <exec executable="${builddir}/go/bin/go" dir="${builddir}/go/src/github.com/mendersoftware/mender-artifact" failonerror="true">
+   <arg line="mod init"/>
+  </exec>
+  <exec executable="${builddir}/go/bin/go" dir="${builddir}/go/src/github.com/mendersoftware/mender-artifact" failonerror="true">
+   <arg line="mod vendor"/>
+  </exec>
   <exec executable="${builddir}/go/bin/go" dir="${builddir}/go/src/github.com/mendersoftware/mender-artifact/cli/mender-artifact" failonerror="true">
    <arg line="build -ldflags &quot;-X main.Version=3.3.0&quot;"/>
   </exec>