fix(ci-broker.md): drop bashism: set -o pipefail. — radicle-ci-broker

On a machine where /bin/sh it not Bash, the pipefail setting will fail.

Signed-off-by: Lars Wirzenius liw@liw.fi

 ~~~{#dummy.sh .file .sh}
 #!/bin/sh
 set -euo pipefail
 set -eu
 cat > /dev/null
 echo '{"response":"triggered","run_id":{"id":"xyzzy"}}'
 echo '{"response":"finished","result":"success"}'

 ~~~{#create-patch .file .sh}
 #!/bin/sh
 set -euo pipefail
 set -eu
 touch foo
 git add foo

 ~~~{#adapter-with-url.sh .file .sh}
 #!/bin/sh
 set -euo pipefail
 set -eu
 echo '{"response":"triggered","run_id":{"id":"xyzzy"},"info_url":"https://ci.example.com/xyzzy"}'
 echo '{"response":"finished","result":"success"}'
 ~~~

 ~~~{#broken-adapter.sh .file .sh}
 #!/bin/sh
 set -euo pipefail
 set -eu
 cat > /dev/null
 echo '{"response":"Rivendell"}}'
 echo "This is an adapter error: Mordor" 1>&2

 ~~~{#count.sh .file .sh}
 #!/bin/sh
 set -euo pipefail
 set -eu
 run() {
 	cibtool --db "$DB" counter count --goal "$goal"

 # verify the CI broker database has the CI runs in the list, plus one
 # more, and then update the list.
 set -euo pipefail
 set -eu
 REPO="testy"