title: Error building project in Heroku (invalid character in key name = ':')
body: <p>I can't build my project in Heroku, crashing on Pipfile. Heroku is linked with my Github repository, which is private for obvious reasons.
  I tried other things too, but when I add 'worker: python bot.py' on Pipfile, it just doesn't build. There's no Pipfile.lock on my project. 
  Logs:</p>
  
  <pre><code>    -----&gt; Python app detected
   !     No 'Pipfile.lock' found! We recommend you commit this into your repository.
  -----&gt; Need to update SQLite3, clearing cache
  -----&gt; Installing python-3.6.9
  -----&gt; Installing pip
  -----&gt; Installing dependencies with Pipenv 2018.5.18…
         Traceback (most recent call last):
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/project.py", line 438, in _parse_pipfile
             return contoml.loads(contents)
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/patched/contoml/__init__.py", line 14, in loads
             tokens = tuple(lexer(text, is_top_level=True))
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/patched/prettytoml/lexer/__init__.py", line 108, in tokenize
             next_row, next_col, source[next_index:]))
         prettytoml.lexer.LexerError: failed to read the next token at (9, 4): : python bot.py
         worker: python bot.py
  
  
         During handling of the above exception, another exception occurred:
  
         Traceback (most recent call last):
           File "/app/.heroku/python/bin/pipenv", line 11, in &lt;module&gt;
             sys.exit(cli())
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 722, in __call__
             return self.main(*args, **kwargs)
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 697, in main
             rv = self.invoke(ctx)
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 1066, in invoke
             return _process_result(sub_ctx.command.invoke(sub_ctx))
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 895, in invoke
             return ctx.invoke(self.callback, **ctx.params)
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/click/core.py", line 535, in invoke
             return callback(*args, **kwargs)
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/cli.py", line 402, in install
             selective_upgrade=selective_upgrade,
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/core.py", line 1785, in do_install
             pre = project.settings.get('allow_prereleases')
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/project.py", line 446, in settings
             return self.parsed_pipfile.get('pipenv', {})
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/project.py", line 392, in parsed_pipfile
             parsed = self._parse_pipfile(contents)
           File "/app/.heroku/python/lib/python3.6/site-packages/pipenv/project.py", line 441, in _parse_pipfile
             return toml.loads(contents)
           File "/tmp/build_97bd7e093c4db06e0905838cbf26d2d1/.heroku/python/lib/python3.6/site-packages/pipenv/vendor/toml.py", line 176, in loads
             item + "'. Try quoting the key name.")
         toml.TomlDecodeError: Found invalid character in key name: ':'. Try quoting the key name.
   !     Push rejected, failed to compile Python app.
   !     Push failed
  </code></pre>
  
  <p>My Pipfile:</p>
  
  <pre><code>[packages] 
  requests = "*"
  python-telegram-bot = "*"
  
  [scripts]
  web: python bot.py
  worker: python bot.py
  </code></pre>
  
  <p>It seems right for me, I don't know what to do...</p>