remove pyyaml from requirements.txt - just make it a travis thing

.travis.yml

@@ -6,7 +6,7 @@ python:
   - "3.8"
   - "3.8-dev"
 install:
-  - pip3 install mypy -r requirements.txt
+  - pip3 install mypy pyyaml==5.3.1
 script:
   - pip3 freeze
   - mypy irctokens

requirements.txt

@@ -1 +0,0 @@
-pyyaml==5.3.1

setup.py

@@ -4,8 +4,6 @@ with open("README.md", "r") as fh:
     long_description = fh.read()
 with open("VERSION", "r") as version_file:
     version = version_file.read().strip()
-with open("requirements.txt", "r") as requirements_file:
-    install_requires = requirements_file.read().splitlines()
 
 setuptools.setup(
     name="irctokens",
@@ -27,5 +25,4 @@ setuptools.setup(
         "Topic :: Communications :: Chat :: Internet Relay Chat"
     ],
     python_requires='>=3.6'
-    install_requires=install_requires
 )