update requirements

requirements.txt

@@ -1,34 +1,34 @@
-build==0.4.0
-certifi==2021.5.30
-chardet==4.0.0
-grpcio==1.37.1
-grpcio-testing==1.37.1
-grpcio-tools==1.37.1
-idna==2.10
+build>=0.4.0
+certifi>=2021.5.30
+chardet>=4.0.0
+grpcio>=1.37.1,<2.0
+grpcio-testing>=1.37.1,<2.0
+grpcio-tools>=1.37.1,<2.0
+idna>=2.10
 mmh3>=2.0,<=3.0.0
-packaging==20.9
-pep517==0.10.0
-protobuf==3.17.1
-pyparsing==2.4.7
-six==1.16.0
-toml==0.10.2
+packaging>=20.9
+pep517>=0.10.0
+protobuf>=3.17.1,<4.0
+pyparsing>=2.4.7
+six>=1.16.0
+toml>=0.10.2
 ujson>=2.0.0,<=5.1.0
-urllib3==1.26.5
+urllib3>=1.26.5
 sklearn==0.0
-m2r==0.2.1
-mistune==0.8.4
-Sphinx==2.3.1
-sphinx-copybutton==0.3.1
-sphinx-rtd-theme==0.4.3
-sphinxcontrib-applehelp==1.0.1
-sphinxcontrib-devhelp==1.0.1
-sphinxcontrib-htmlhelp==1.0.2
-sphinxcontrib-jsmath==1.0.1
-sphinxcontrib-qthelp==1.0.2
-sphinxcontrib-serializinghtml==1.1.3
+m2r>=0.2.1
+mistune>=0.8.4
+Sphinx>=2.3.1
+sphinx-copybutton>=0.3.1
+sphinx-rtd-theme>=0.4.3
+sphinxcontrib-applehelp>=1.0.1
+sphinxcontrib-devhelp>=1.0.1
+sphinxcontrib-htmlhelp>=1.0.2
+sphinxcontrib-jsmath>=1.0.1
+sphinxcontrib-qthelp>=1.0.2
+sphinxcontrib-serializinghtml>=1.1.3
 sphinxcontrib-prettyspecialmethods
-pytest==5.3.4
-pytest-cov==2.8.1
-pytest-timeout==1.3.4
-pylint==2.4.4
+pytest>=5.3.4
+pytest-cov>=2.8.1
+pytest-timeout>=1.3.4
+pylint>=2.4.4
 pandas>=1.1.5