Lock memchr version to support edition 2018

memchr 2.5.0 is the last version that supports edition 2018. lock the
version in Cargo.toml

Bug: 297895455
Change-Id: If51fa5ba9e284ade71b49013f5e8980bc19539c8
1 file changed
tree: d1025b1d738650f07d36dc730d308935661e2b51
  1. app/
  2. blob_fs/
  3. capsules/
  4. config/
  5. hal/
  6. platform/
  7. utils/
  8. .gitignore
  9. matcha.code-workspace