fix(calamares): force HTTP/1.1 and add retries to Codeberg download

Codeberg's HTTP/2 endpoint is flaky and resets connections on
calamares-3.4.2.tar.gz. Forcing --http1.1 with --retry 5 avoids
the 'HTTP/2 stream 7 reset by server' error.

DLAGENTS in PKGBUILD is supported — Arch BBS and makepkg source
confirm it's read from the shell environment after sourcing.

packages/calamares/PKGBUILD

@@ -28,6 +28,7 @@ makedepends=(
 )
 
 _pkgext="tar.gz"
+DLAGENTS=('https::/usr/bin/curl -gqb "" -fLC - --http1.1 --retry 5 --retry-delay 5 -o %o %u')
 source=("$_pkgname-$pkgver.$_pkgext"::"$url/releases/download/v$pkgver/$_pkgname-$pkgver.$_pkgext")
 sha256sums=('733bbbb00dc9f84874bd5c22960952f317ea2537565431179fa2152b2fbfdccc')