Cirrus-CI: stop forcibly installing pkg

Updated pkg is now in quarterly and there is no need to forcibly
install a specific version.

This reverts commit 1c376684c7.
This reverts commit 3c097b06a7.

Reported by:	bapt
Sponsored by:	The FreeBSD Foundation

.cirrus.yml

@@ -93,11 +93,6 @@ task:
   install_script:
   - sh .cirrus-ci/pkg-install.sh ${TOOLCHAIN_PKG} git-lite
 
-  xxx_upgrade_pkg_script:
-  - fetch https://pkg.freebsd.org/FreeBSD:13:amd64/latest/All/pkg-1.20.9.pkg
-  - pkg install -y ./pkg-1.20.9.pkg
-  - rm -f pkg-1.20.9.pkg
-
   setup_script:
   - uname -a
   - gpart show