Changes on the requirements file to remove dependencies

Author: pedrominatel

docs/requirements.txt

@@ -1,15 +1,4 @@
-esp-docs==1.4.*
+# add esp-docs version superior or equal to 1.4
+esp-docs>=1.4.0
 sphinx-copybutton==0.5.0
 sphinx-tabs==3.2.0
-sphinxcontrib-actdiag==3.0.0
-sphinxcontrib-applehelp==1.0.4
-sphinxcontrib-blockdiag==3.0.0
-sphinxcontrib-devhelp==1.0.2
-sphinxcontrib-htmlhelp==2.0.1
-sphinxcontrib-jsmath==1.0.1
-sphinxcontrib-nwdiag==2.0.0
-sphinxcontrib-qthelp==1.0.3
-sphinxcontrib-seqdiag==3.0.0
-sphinxcontrib-serializinghtml==1.1.5
-sphinxcontrib-svg2pdfconverter==1.2.0
-sphinxcontrib-wavedrom==3.0.4