Shorten the CHANGELOG.md preambles

The previous version was unnecessarily verbose and included
developer information about using scriv that is not likely to be
of interest to the target audience. Omit the note about updating
dependencies for PyPI apps; those changes aren't done automatically
with PyPI apps and may be significant enough to note in the change
log.

project_templates/fastapi_safir_app/{{cookiecutter.name}}/CHANGELOG.md

@@ -1,12 +1,8 @@
 # Change log
 
-All notable changes to {{cookiecutter.name}} will be documented in this file.
+{{cookiecutter.name}} is versioned with [semver](https://semver.org/).
+Dependencies are updated to the latest available version during each release, and aren't noted here.
 
-Versioning follows [semver](https://semver.org/).
-
-Dependencies are updated to the latest available version during each release. Those changes are not noted here explicitly.
-
-This project uses [scriv](https://scriv.readthedocs.io/en/stable/) to maintain the change log.
-Changes for the upcoming release can be found in [changelog.d](https://github.com/{{cookiecutter.github_org}}/{{cookiecutter.name}}/tree/main/changelog.d/).
+Find changes for the upcoming release in the project's [changelog.d directory](https://github.com/{{cookiecutter.github_org}}/{{cookiecutter.name}}/tree/main/changelog.d/).
 
 <!-- scriv-insert-here -->

project_templates/square_pypi_package/{{cookiecutter.name}}/CHANGELOG.md

@@ -1,12 +1,7 @@
 # Change log
 
-All notable changes to {{cookiecutter.name}} will be documented in this file.
+{{cookiecutter.name}} is versioned with [semver](https://semver.org/).
 
-Versioning follows [semver](https://semver.org/).
-
-Dependencies are updated to the latest available version during each release. Those changes are not noted here explicitly.
-
-This project uses [scriv](https://scriv.readthedocs.io/en/stable/) to maintain the change log.
-Changes for the upcoming release can be found in [changelog.d](https://github.com/{{cookiecutter.github_org}}/{{cookiecutter.name}}/tree/main/changelog.d/).
+Find changes for the upcoming release in the project's [changelog.d directory](https://github.com/{{cookiecutter.github_org}}/{{cookiecutter.name}}/tree/main/changelog.d/).
 
 <!-- scriv-insert-here -->