clean up python_version specifiers from requirements files

requires-celery.txt

@@ -1,4 +1,3 @@
 # Dependencies used by the CeleryLongCallbackManager
 redis>=3.5.3
 celery[redis]>=5.1.2
-importlib-metadata<5;python_version<"3.8"

requires-ci.txt

@@ -1,27 +1,21 @@
 # Dependencies used by CI on github.com/plotly/dash
-black==22.3.0;python_version>="3.7"
-black==21.6b0;python_version<"3.7"
+black==22.3.0
 dash-flow-example==0.0.5
 dash-dangerously-set-inner-html
 flake8==7.0.0
 flaky==3.7.0
 flask-talisman==1.0.0
-isort==4.3.21;python_version<"3.7"
 mimesis<=11.1.0
 mock==4.0.3
 numpy<=1.26.3
-orjson==3.5.4;python_version<"3.7"
-orjson==3.9.12;python_version>="3.7"
-openpyxl;python_version>="3.8"
-pandas>=1.4.0;python_version>="3.8"
-pandas==1.1.5;python_version<"3.8"
-pyarrow<3;python_version<"3.7"
-pyarrow;python_version>="3.7"
+orjson==3.9.12
+openpyxl
+pandas>=1.4.0
+pyarrow
 pylint==3.0.3
 pytest-mock
 pytest-sugar==0.9.6
 pyzmq==25.1.2
-xlrd>=2.0.1;python_version>="3.8"
-xlrd<2;python_version<"3.8"
+xlrd>=2.0.1
 pytest-rerunfailures
 jupyterlab<4.0.0

requires-install.txt

@@ -4,9 +4,7 @@ plotly>=5.0.0
 dash_html_components==2.0.0
 dash_core_components==2.0.0
 dash_table==5.0.0
-importlib-metadata==4.8.3;python_version<"3.7"
-importlib-metadata;python_version>="3.7"
-contextvars==2.4;python_version<"3.7"
+importlib-metadata
 typing_extensions>=4.1.1
 requests
 retrying