Drop support for Python 3.6

Now that Qiskit Aer 0.10.0 has been released that Qiskit no longer
supports python 3.6 (in the lead up to adding support for python 3.10).
This commit officially drops the support for python 3.6 and makes python
3.7 required to install qiskit-aer. It also removes all the ci jobs
still using 3.6 both for testing and building wheels.

.github/workflows/build.yml

@@ -136,7 +136,7 @@ jobs:
       - name: Build Wheels
         env:
           CIBW_BEFORE_ALL_LINUX: "yum install -y openblas-devel"
-          CIBW_SKIP: "cp310-* pp*"
+          CIBW_SKIP: "cp36-*" "cp310-* pp*"
           CIBW_TEST_COMMAND: "python {project}/tools/verify_wheels.py"
           CIBW_ENVIRONMENT_WINDOWS: "CMAKE_GENERATOR='Visual Studio 16 2019'"
         run: cibuildwheel --output-dir wheelhouse

.github/workflows/deploy.yml

@@ -22,7 +22,7 @@ jobs:
       - name: Build wheels
         env:
           CIBW_BEFORE_ALL_LINUX: "yum install -y openblas-devel"
-          CIBW_SKIP: "cp310-* pp*"
+          CIBW_SKIP: "cp36-*" "cp310-* pp*"
           CIBW_TEST_COMMAND: "python {project}/tools/verify_wheels.py"
           CIBW_ENVIRONMENT_WINDOWS: "CMAKE_GENERATOR='Visual Studio 16 2019'"
         run: |
@@ -65,7 +65,7 @@ jobs:
           python -m cibuildwheel --output-dir wheelhouse
         env:
           CIBW_BEFORE_ALL_LINUX: "yum install -y https://dl.fedoraproject.org/pub/epel/7/aarch64/Packages/e/epel-release-7-12.noarch.rpm && yum install -y openblas-devel"
-          CIBW_SKIP: "cp310-* pp*"
+          CIBW_SKIP: "cp36-*" "cp310-* pp*"
           CIBW_TEST_COMMAND: "python {project}/tools/verify_wheels.py"
           CIBW_ARCHS_LINUX: aarch64
       - uses: actions/upload-artifact@v2
@@ -117,7 +117,7 @@ jobs:
       - name: Build wheels
         env:
           CIBW_BEFORE_ALL: "yum install -y yum-utils wget && wget https://developer.download.nvidia.com/compute/cuda/10.1/Prod/local_installers/cuda-repo-rhel6-10-1-local-10.1.243-418.87.00-1.0-1.x86_64.rpm && rpm -i cuda-repo-rhel6-10-1-local-10.1.243-418.87.00-1.0-1.x86_64.rpm && yum clean all && yum -y install cuda-10-1 openblas-devel"
-          CIBW_SKIP: "cp310-* *-manylinux_i686 pp*"
+          CIBW_SKIP: "cp36-*" "cp310-* *-manylinux_i686 pp*"
           CIBW_ENVIRONMENT: QISKIT_AER_PACKAGE_NAME=qiskit-aer-gpu AER_THRUST_BACKEND=CUDA CUDACXX=/usr/local/cuda/bin/nvcc
           CIBW_TEST_COMMAND: "python {project}/tools/verify_wheels.py"
         run: |

.github/workflows/tests_linux.yml

@@ -89,7 +89,7 @@ jobs:
     timeout-minutes: 60
     strategy:
       matrix:
-        python-version: [3.6, 3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9]
         os: ["ubuntu-latest"]
     env:
       AER_THRUST_BACKEND: OMP
@@ -113,7 +113,6 @@ jobs:
         run: python -m pip install -U -c constraints.txt -r requirements-dev.txt wheel
       - name: Install terra from source
         run: python -m pip install -U -c constraints.txt git+https://github.com/Qiskit/qiskit-terra
-        if: matrix.python-version != '3.6'
       - name: Install openblas
         run: |
           set -e

setup.py

@@ -131,13 +131,12 @@ def install_needed_req(import_name, package_name=None, min_version=None, max_ver
         "Operating System :: POSIX :: Linux",
         "Programming Language :: C++",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Topic :: Scientific/Engineering",
     ],
-    python_requires=">=3.6",
+    python_requires=">=3.7",
     install_requires=requirements,
     setup_requires=setup_requirements,
     include_package_data=True,

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.1
-envlist = py36, py37, py38, py39, lint
+envlist = py37, py38, py39, lint
 skipsdist = True
 
 [testenv]