Heroku one-click deployment fails

[crd]

The one-click deployment (without touching parameters) fails. Build log contains:

-----> VIPS app detected
-----> Installing libvips
       Downloading libvips and unpacking
       libvips installed
-----> Node.js app detected

-----> Creating runtime environment

       NPM_CONFIG_LOGLEVEL=error
       NPM_CONFIG_PRODUCTION=false
       NODE_ENV=production
       NODE_MODULES_CACHE=true
       NODE_VERBOSE=false

-----> Installing binaries
       engines.node (package.json):  >=8.0.0
       engines.npm (package.json):   unspecified (use default)
       engines.yarn (package.json):  unspecified (use default)

       Resolving node version >=8.0.0...
       Downloading and installing node 13.0.1...
       Using default npm version: 6.12.0
       Resolving yarn version 1.x...
       Downloading and installing yarn (1.19.1)...
       Installed yarn 1.19.1

-----> Installing dependencies
       Installing node modules (yarn.lock)
       yarn install v1.19.1
       [1/4] Resolving packages...
       warning @hackmd/codemirror > phantomjs-prebuilt@2.1.16: this package is now deprecated
       warning @hackmd/codemirror > rollup-watch@4.3.1: rollup-watch functionality is now included in Rollup itself
       warning @hackmd/codemirror > rollup-plugin-buble > buble > os-homedir@2.0.0: This is not needed anymore. Use `require('os').homedir()` instead.
       warning @hackmd/codemirror > blint > nomnom@1.8.1: Package no longer supported. Contact support@npmjs.com for more info.
       error Your lockfile needs to be updated, but yarn was run with `--frozen-lockfile`.
       info Visit https://yarnpkg.com/en/docs/cli/install for documentation about this command.
-----> Build failed
 !     Outdated Yarn lockfile
       Your application contains a Yarn lockfile (yarn.lock) which does not
       match the dependencies in package.json. This can happen if you use npm
       to install or update a dependency instead of Yarn.
       Please run the following command in your application directory and check
       in the new yarn.lock file:
       $ yarn install
       $ git add yarn.lock
       $ git commit -m "Updated Yarn lockfile"
       $ git push heroku master

       https://help.heroku.com/TXYS53YJ
 !     Push rejected, failed to compile Node.js app.
 !     Push failed

[jackycute]

Hi @crd,

This issue is duplicated with #1311 Please see: https://github.com/hackmdio/codimd/issues/1311#issuecomment-545225839

[crd]

Closed as duplicate. Thanks!