sagemathgh-36781: `libbraiding`: Actually update to version 1.2
    
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As previously observed in sagemath#36283, the intended upgrade of libbraiding to
1.2 as part of sagemath#35380 was faulty, and as a result we have a
`libbraiding-1.2.tar.gz` on our mirrors that is actually 1.1.

Here we rectify the situation.

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### ⌛ Dependencies

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URL: sagemath#36781
Reported by: Matthias Köppe
Reviewer(s): Dima Pasechnik

Author: Release Manager

build/pkgs/libbraiding/checksums.ini

@@ -1,5 +1,5 @@
-tarball=libbraiding-VERSION.tar.gz
-sha1=06610e47eb243b27aea0ad399b41614fcdb179c9
-md5=5466605026b90bdca7ca20852f88b5c5
-cksum=704753563
-upstream_url=https://github.com/miguelmarco/libbraiding/releases/download/1.1/libbraiding-1.1.tar.gz
+tarball=libbraiding-VERSION-actually-VERSION.tar.gz
+sha1=b7e13778784fe1e36e7c0cbd7a4c234a090cd1b2
+md5=0513967c81b783ea66336b7ad0562534
+cksum=3619705925
+upstream_url=https://github.com/miguelmarco/libbraiding/releases/download/VERSION/libbraiding-VERSION.tar.gz