added upgrade single contract

.solcover.js

@@ -1,4 +1,3 @@
 module.exports = {
-  skipFiles: ['imports', 'mocks'],
-  deepSkip: true
+  skipFiles: ['imports']
 };

contracts/Master.sol

@@ -99,6 +99,14 @@ contract Master is Ownable {
         changeAllAddress();
     }
 
+    /// @dev upgrades a single contract
+    function upgradeContract(bytes2 _contractsName, address _contractsAddress) public {
+        require(isAuth());
+        allContractVersions[versionDates.length - 1][_contractsName] = _contractsAddress;
+        changeMasterAddress(address(this));
+        changeAllAddress();
+    }
+
     /// @dev sets dAppTokenProxy address
     /// @param _dAppTokenProxy token proxy address
     function setDAppTokenProxy(address _dAppTokenProxy) public {

test/08_Master.js

@@ -139,6 +139,18 @@ contract('Master', function([owner, notOwner]) {
     assert.equal(b.toNumber() + 10, b2.toNumber() - b1.toNumber());
   });
 
+  it('Should upgrade contract', async function() {
+    this.timeout(100000);
+    const poo = await Pool.new();
+    await ms.upgradeContract('PL', poo.address);
+    assert(
+      await ms.getLatestAddress('PL'),
+      poo.address,
+      'contract not upgraded'
+    );
+    await catchRevert(ms.upgradeContract('PL', owner, { from: notOwner }));
+  });
+
   it('Should add new contract', async function() {
     this.timeout(100000);
     // Will throw once owner's permissions are removed. will need to create proposal then.