docs: add changelog and upgrade for v4.5.1

docs: fix typo in upgrade_450

Because php-cs-fixer moves the comment line.

docs: change comment position in Tutorial code

TypeError: str_contains(): Argument #1 ($haystack) must be of type string, null given

chore: add .htaccess and index.html for consistency

docs: fix files in "All Changes" in Project Files in upgrade_448.rst

See #8734

fix: TypeError in form()

fix: [DebugBar] TypeError in Toolbar

fix: update `debugbar:clear` code because of file changes

fix: TypeError when Time is passed to Model

docs: update RELEASE.md

test: refactor Config/Registrar.php

…eady in use

See codeigniter4/shield#1091

If a dev changes CSS for h1, the toolbar dislpay will be broken.

See "Table 33.1. SSL Mode Descriptions"
in https://www.postgresql.org/docs/12/libpq-ssl.html#LIBPQ-SSL-PROTECTION

Make the same as the main repositoy's phpunit.xml.dist.

No change will be made.

…nnot-declare-class

fix: [FileLocator] Cannot declare class XXX, because the name is already in use

…me is already in use

See #8745 (comment)

docs: add "Upgrading to a Specified Version"

Fix "a HTTP" to "an HTTP"

Fix "a HTTP" to "an HTTP".

docs: Small typo in controllers.rst

docs: Small typo in routing.rst

fix: [DebugBar] Toolbar display may be broken

chore: move PHPUnit cache to build/

…nnot-declare-class-v3

fix: Cannot declare class CodeIgniter\Config\Services, because the name is already in use

docs: fix Postgre DSN sample

Prep for 4.5.1 release