fix: Do not prevent to run on tag triggered builds

No reason to prevent a to run on a tag build. On a tag created by semantic-release, no release will be done as no new commits will be added.

index.js

@@ -1,7 +1,6 @@
 const {parse} = require('url');
 const GitHubApi = require('github');
 const parseGithubUrl = require('parse-github-url');
-const semver = require('semver');
 const deployOnce = require('travis-deploy-once');
 const SemanticReleaseError = require('@semantic-release/error');
 const resolveConfig = require('./lib/resolve-config');
@@ -25,17 +24,6 @@ module.exports = async function(pluginConfig, {options: {branch, repositoryUrl}}
     );
   }
 
-  if (process.env.TRAVIS_TAG) {
-    let errorMessage = 'This test run was triggered by a git tag and therefore a new version won’t be published.';
-
-    if (semver.valid(process.env.TRAVIS_TAG)) {
-      errorMessage +=
-        '\nIt is very likely that this tag was created by semantic-release itself.\nEverything is okay. For log output of the actual publishing process look at the build that ran before this one.';
-    }
-
-    throw new SemanticReleaseError(errorMessage, 'EGITTAG');
-  }
-
   if (branch !== process.env.TRAVIS_BRANCH) {
     throw new SemanticReleaseError(
       `This test run was triggered on the branch ${

package.json

@@ -15,7 +15,6 @@
     "@semantic-release/error": "^2.0.0",
     "github": "^12.0.0",
     "parse-github-url": "^1.0.1",
-    "semver": "^5.0.3",
     "travis-deploy-once": "^3.0.0"
   },
   "devDependencies": {

test/condition-travis-test.js

@@ -17,7 +17,6 @@ test.beforeEach(t => {
   delete process.env.GITHUB_PREFIX;
   delete process.env.TRAVIS;
   delete process.env.TRAVIS_PULL_REQUEST;
-  delete process.env.TRAVIS_TAG;
   delete process.env.TRAVIS_BRANCH;
   delete process.env.TRAVIS;
 });
@@ -53,34 +52,6 @@ test.serial('Not running on pull requests', async t => {
   t.true(travisDeployOnce.notCalled);
 });
 
-test.serial('Not running on tags', async t => {
-  const travisDeployOnce = stub();
-  const condition = proxyquire('../', {'travis-deploy-once': travisDeployOnce});
-  process.env.TRAVIS = 'true';
-  process.env.TRAVIS_PULL_REQUEST = 'false';
-  process.env.TRAVIS_TAG = 'v1.0.0';
-
-  const error = await t.throws(condition({}, {options: {}}));
-
-  t.true(error instanceof SemanticReleaseError);
-  t.is(error.code, 'EGITTAG');
-  t.true(travisDeployOnce.notCalled);
-});
-
-test.serial('Not running on tags that don’t look like semantic versions', async t => {
-  const travisDeployOnce = stub();
-  const condition = proxyquire('../', {'travis-deploy-once': travisDeployOnce});
-  process.env.TRAVIS = 'true';
-  process.env.TRAVIS_PULL_REQUEST = 'false';
-  process.env.TRAVIS_TAG = 'vfoo';
-
-  const error = await t.throws(condition({}, {options: {}}));
-
-  t.true(error instanceof SemanticReleaseError);
-  t.is(error.code, 'EGITTAG');
-  t.true(travisDeployOnce.notCalled);
-});
-
 test.serial('Does not run on non-master branch by default', async t => {
   const travisDeployOnce = stub();
   const condition = proxyquire('../', {'travis-deploy-once': travisDeployOnce});