Merge pull request #824 from ethereum/example

correct example for import with url

apps/remix-ide/src/app/ui/landing-page/landing-page.js

@@ -401,7 +401,7 @@ export class LandingPage extends ViewPlugin {
                         <button class="btn mx-1 btn-secondary" onclick="${() => load('Github', 'github URL', ['https://github.com/0xcert/ethereum-erc721/src/contracts/tokens/nf-token-metadata.sol', 'https://github.com/OpenZeppelin/openzeppelin-solidity/blob/67bca857eedf99bf44a4b6a0fc5b5ed553135316/contracts/access/Roles.sol', 'github:OpenZeppelin/openzeppelin-solidity/contracts/ownership/Ownable.sol#v2.1.2'])}">GitHub</button>
                         <button class="btn mx-1 btn-secondary" onclick="${() => load('Swarm', 'bzz-raw URL', ['bzz-raw://<swarm-hash>'])}">Swarm</button>
                         <button class="btn mx-1 btn-secondary" onclick="${() => load('Ipfs', 'ipfs URL', ['ipfs://<ipfs-hash>'])}">Ipfs</button>
-                        <button class="btn mx-1 btn-secondary" onclick="${() => load('Https', 'http/https raw content', ['https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/master/contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol'])}">https</button>
+                        <button class="btn mx-1 btn-secondary" onclick="${() => load('Https', 'http/https raw content', ['https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-contracts/master/contracts/token/ERC20/ERC20.sol'])}">https</button>
                         <button class="btn mx-1 btn-secondary  text-nowrap" onclick="${() => load('@resolver-engine', 'resolver-engine URL', ['github:OpenZeppelin/openzeppelin-solidity/contracts/ownership/Ownable.sol#v2.1.2'], yo`<span>please checkout <a class='text-primary' href="https://github.com/Crypto-Punkers/resolver-engine" target='_blank'>https://github.com/Crypto-Punkers/resolver-engine</a> for more information</span>`)}">Resolver-engine</button>
                       </div><!-- end of btn-group -->
                     </div><!-- end of div.file -->