Remove overly aggresive pinning from requirements (#1605)

This commit removes overly aggressive pinning from the requirements
list. This pinning makes it extremely difficult in practice to actually
install the qiskit-aqua with anything that has any shared dependencies
like numpy, scipy, etc because the pinning breaks the dependency solver.
I assume this pinning was done defensively to try and prevent code from
bit rotting during aqua's deprecation period but it has the opposite
effect and ends up preventing things from being installed at all. This
commit removes all the version caps from the requirements file to fix
this.

requirements.txt

@@ -1,18 +1,18 @@
-qiskit-terra>=0.17.0,<0.19.0
-qiskit-ignis>=0.6.0,<0.8.0
-scipy>=1.4,<=1.6.1
-sympy>=1.3,<=1.7.1
-numpy>=1.17,<=1.20.1
-psutil>=5,<=5.8.0
-scikit-learn>=0.20.0,<=0.24.1
+qiskit-terra>=0.17.0
+qiskit-ignis>=0.6.0
+scipy>=1.4
+sympy>=1.3
+numpy>=1.17
+psutil>=5
+scikit-learn>=0.20.0
 dlx<=1.0.4
 docplex<=2.20.204; sys_platform != 'darwin'
 docplex==2.15.194; sys_platform == 'darwin'
 fastdtw<=0.3.4
 setuptools>=40.1.0
-h5py<=3.1.0
-pandas<=1.2.3
-quandl<=3.6.0
-yfinance<=0.1.55
-retworkx>=0.8.0,<0.10.0
+h5py
+pandas
+quandl
+yfinance
+retworkx>=0.8.0
 dataclasses; python_version < '3.7'