Bump qiskit-symb from 0.2.0 to 0.3.0

Bumps [qiskit-symb](https://github.com/SimoneGasperini/qiskit-symb) from 0.2.0 to 0.3.0.
- [Release notes](https://github.com/SimoneGasperini/qiskit-symb/releases)
- [Commits](SimoneGasperini/qiskit-symb@v0.2.0...v0.3.0)

---
updated-dependencies:
- dependency-name: qiskit-symb
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

doc/requirements.txt

@@ -23,5 +23,5 @@ moabb==1.1.1
 pyriemann==0.6
 docplex>=2.21.207
 firebase_admin==6.6.0
-qiskit-symb==0.2.0
+qiskit-symb==0.3.0
 symengine==0.11.0

setup.py

@@ -63,7 +63,7 @@
                       'tests': ['pytest', 'seaborn', 'flake8', 'mne', 'pooch'],
                       # GPU optimization not available on all platform.
                       # See https://github.com/Qiskit/qiskit-aer/issues/929#issuecomment-691716936
-                      'optim': ['qiskit-symb==0.2.0', 'symengine==0.11.0'],
+                      'optim': ['qiskit-symb==0.3.0', 'symengine==0.11.0'],
                       'optim_linux': ['qiskit-aer-gpu==0.15.1']},
       zip_safe=False,
 )