obmc-build-script: Update fmt to `8.1.1`
obmc-build-script: Update fmt to `8.1.1`

Match the version in
https://github.com/openbmc/openbmc/blob/595f63084d313c9708cb435470e6c6dcbbbbe646/meta-openembedded/meta-oe/recipes-support/fmt/fmt_8.1.1.bb

Change-Id: Ib647c4f54dfb1a6e619200247a6c4a9f95037140
Signed-off-by: Willy Tu <1e3df9bf0ac020872e0e39905eae1676fb455af4@google.com>

openbmc/openbmc-build-scripts,openbmc/openbmc-build-scripts