Project.toml: pin SPIRVIntrinsics [sources] to a commit SHA

rev = "atomic-float-ops" tracked a mutable branch head, so builds were not
reproducible and a force-push to the fork would silently change what users
resolve. Pin to commit 4257d40, whose lib/intrinsics subtree matches the
currently resolved Manifest exactly (git-tree-sha1 87509a31), so this is a
no-op today but freezes the input going forward.

Addresses PR_REVIEW.md additional observation (mutable [sources] branch pin).

Author: michel2323

Project.toml

@@ -58,4 +58,6 @@ oneAPI_Support_jll = "0.9.2"
 libigc_LTS_jll = "9a8258a1-e827-5686-bee9-144461246960"
 
 [sources]
-SPIRVIntrinsics = {url = "https://github.com/michel2323/OpenCL.jl", rev = "atomic-float-ops", subdir = "lib/intrinsics"}
+# Pin to a commit SHA, not the mutable `atomic-float-ops` branch head, so builds are
+# reproducible and a force-push upstream cannot silently change what users resolve.
+SPIRVIntrinsics = {url = "https://github.com/michel2323/OpenCL.jl", rev = "4257d4075162276d9985168923788490e4071e9e", subdir = "lib/intrinsics"}