build: switch to python3

Refs: #5095
Change-Id: Iedc107d41d4832682071986678b015980354786d
diff --git a/docs/release-notes/release-notes-0.6.1.rst b/docs/release-notes/release-notes-0.6.1.rst
index 2770915..c1f5a4f 100644
--- a/docs/release-notes/release-notes-0.6.1.rst
+++ b/docs/release-notes/release-notes-0.6.1.rst
@@ -13,50 +13,40 @@
 - New signal in :ndn-cxx:`SegmentFetcher` to notify retrieval of Data segments
   (:issue:`4438`)
 
-- Initial support for the Content Store management protocol
-  (:issue:`4050`)
+- Initial support for the Content Store management protocol (:issue:`4050`)
 
 - Literal operators for ``time::duration`` types, such as ``1_s``, ``42_ms``, ``30_days``
   (:issue:`4468`)
 
 - Support for BLAKE2 hash function (requires OpenSSL >= 1.1.0)
 
-- A ``escape()`` helper function complementing the existing ``unescape()`` (:issue:`4484`)
+- An ``escape()`` helper function complementing the existing ``unescape()`` (:issue:`4484`)
 
 Improvements and bug fixes
 ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 - ``ndnsec key-gen`` command line now allows customization of key ID (:issue:`4294`)
 
-- Fixed encoding of ``'~'`` and ``'+'`` in :ndn-cxx:`Component::toUri()`
-  (:issue:`4484`)
+- Fixed encoding of ``'~'`` and ``'+'`` in ``name::Component::toUri()`` (:issue:`4484`)
 
-- Fixed handling of large dates when converting to/from string
-  (:issue:`4478`, :issue:`3915`)
+- Fixed handling of large dates when converting to/from string (:issue:`4478`, :issue:`3915`)
 
-- Fixed error handling in :ndn-cxx:`KeyChain::importSafeBag()`
-  (:issue:`4359`)
+- Fixed error handling in ``KeyChain::importSafeBag()`` (:issue:`4359`)
 
-- Fixed parsing of IPv6 addresses with scope-id
-  (:issue:`4474`)
+- Fixed parsing of IPv6 addresses with scope-id (:issue:`4474`)
 
-- :ndn-cxx:`io::load()` now handles empty files properly
-  (:issue:`4434`)
+- ``io::load()`` now handles empty files properly (:issue:`4434`)
 
-- Switched to using `boost::asio::basic_waitable_timer`
-  (:issue:`4431`)
+- Switched to using ``boost::asio::basic_waitable_timer`` (:issue:`4431`)
 
-- Allow linking multiple :ndn-cxx:`DummyClientFace` instances together to emulate a broadcast medium
-  (:issue:`3913`)
+- Allow linking multiple :ndn-cxx:`DummyClientFace` instances together to emulate a broadcast
+  medium (:issue:`3913`)
 
-- Fixed build when ``std::to_string`` is not available
-  (:issue:`4393`)
+- Fixed build when ``std::to_string`` is not available (:issue:`4393`)
 
-- Avoid undefined behavior when casting to :ndn-cxx:`tlv::SignatureTypeValue`
-  (:issue:`4370`)
+- Avoid undefined behavior when casting to :ndn-cxx:`tlv::SignatureTypeValue` (:issue:`4370`)
 
-- Fixed compilation with Boost 1.66.0
-  (:issue:`4422`)
+- Fixed compilation with Boost 1.66.0 (:issue:`4422`)
 
 - Various documentation updates
   (:issue:`3918`, :issue: `4184`, :issue: `4275`)
@@ -64,6 +54,4 @@
 Removed
 ^^^^^^^
 
-- Removed obsolete TLV-TYPE constants
-  (:issue:`4055`, :issue:`3098`, :issue: `3755`)
-
+- Removed obsolete TLV-TYPE constants (:issue:`4055`, :issue:`3098`, :issue: `3755`)