ci: prevent `perforce` from being quarantined

The most recent Azure Pipelines macOS agents enable what Apple calls
"System Integrity Protection". This makes `p4d -V` hang: there is some
sort of GUI dialog waiting for the user to acknowledge that the copied
binaries are legit and may be executed, but on build agents, there is no
user who could acknowledge that.

Let's ask Homebrew specifically to _not_ quarantine the Perforce
binaries.

Helped-by: Aleksandr Chebotov
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ci/install-dependencies.sh

@@ -40,11 +40,11 @@ osx-clang|osx-gcc)
 	test -z "$BREW_INSTALL_PACKAGES" ||
 	brew install $BREW_INSTALL_PACKAGES
 	brew link --force gettext
-	brew cask install perforce || {
+	brew cask install --no-quarantine perforce || {
 		# Update the definitions and try again
 		cask_repo="$(brew --repository)"/Library/Taps/homebrew/homebrew-cask &&
 		git -C "$cask_repo" pull --no-stat &&
-		brew cask install perforce
+		brew cask install --no-quarantine perforce
 	} ||
 	brew install caskroom/cask/perforce
 	case "$jobname" in