Prepare 0.7 release (#1267)

* Prepare 0.7 release

* docs: touch up on some release notes

Author: mrossinek

docs/migration/index.rst

@@ -2,6 +2,9 @@
 Qiskit Nature Migration Guides
 ##############################
 
+If you are switching over to version 0.7, which has removed all previously
+deprecated code, simply follow the instructions provided in the sections below.
+
 Migrating from 0.5 to 0.6
 -------------------------
 

releasenotes/notes/0.7-prelude-169d294985170fd5.yaml

@@ -0,0 +1,20 @@
+---
+prelude: >
+  Qiskit Nature has been migrated to the `qiskit-community Github organization <https://github.com/qiskit-community>`_
+  to further emphasize that it is a community-driven project.
+  To reflect this change and because we are onboarding additional codeowners and maintainers,
+  with this version (0.7) we have decided to *remove all deprecated* code, regardless of the time of its deprecation.
+  This ensures that the new members of the development team do not have a large bulk of legacy code to maintain.
+
+  This can mean one of two things for you as the end-user:
+
+    #. Nothing, if you already migrated your code and no longer rely on any deprecated features.
+
+    #. Otherwise, you need to migrate your code immediately. If you cannot do that, or want to continue using some
+       of the features that were removed, you should pin your version of Qiskit Nature to 0.6
+
+  You can check out the `migration guides <https://qiskit.org/ecosystem/nature/migration/index.html>`_
+  for details on how to update your code.
+
+  For more context on the changes around Qiskit Nature and the other application projects as well as the algorithms
+  library in Qiskit, be sure to read this `blog post <https://ibm.biz/BdSyNm>`_.

releasenotes/notes/0.7/0.7-prelude-169d294985170fd5.yaml

@@ -4,11 +4,11 @@ features:
     Adds new operator generator functions to allow more fine-grained spin observables.
     The new functions are:
 
-    - the $S^+$ operator: :func:`.s_plus_operator`
-    - the $S^-$ operator: :func:`.s_minus_operator`
-    - the $S^x$ operator: :func:`.s_x_operator`
-    - the $S^y$ operator: :func:`.s_y_operator`
-    - the $S^z$ operator: :func:`.s_z_operator`
+    - the :math:`S^+` operator: :func:`.s_plus_operator`
+    - the :math:`S^-` operator: :func:`.s_minus_operator`
+    - the :math:`S^x` operator: :func:`.s_x_operator`
+    - the :math:`S^y` operator: :func:`.s_y_operator`
+    - the :math:`S^z` operator: :func:`.s_z_operator`
 
     All of these functions take the number of spatial orbitals as their only argument
     and return the constructed :class:`.FermionicOp`.

releasenotes/notes/add-hexagonal-lattice-a981f1b5c832a154.yaml renamed to releasenotes/notes/0.7/add-hexagonal-lattice-a981f1b5c832a154.yaml

@@ -17,7 +17,7 @@ features:
   - |
     In order to use the bosonic operator for quantum applications, this feature also introduces the
     bosonic linear mapper, which allows to map the BosonicOp to the qubit space. This mapper is based
-    on `this paper <https://link.aps.org/doi/10.1103/PhysRevResearch.3.043212>`.
+    on `this paper <https://link.aps.org/doi/10.1103/PhysRevResearch.3.043212>`_.
     To use this mapper one can for example:
 
     .. code-block:: python