chore: update msrv to 1.87 (#1597)

Unfortunately, as tends to happen, the ground has shifted beneath our
feet, and we now need MSRV 1.87 to run with our dependencies. The good
news is that this will allow us to go to the 2024 edition. Onwards and
upwards!

Author: akern40

.github/workflows/ci.yaml

@@ -14,8 +14,8 @@ env:
   HOST: x86_64-unknown-linux-gnu
   FEATURES: "approx,serde,rayon"
   RUSTFLAGS: "-D warnings"
-  MSRV: 1.64.0
-  BLAS_MSRV: 1.71.1
+  MSRV: 1.87.0
+  BLAS_MSRV: 1.87.0
 
 jobs:
   pass-msrv:

.github/workflows/latest-deps.yaml

@@ -17,8 +17,7 @@ env:
   HOST: x86_64-unknown-linux-gnu
   FEATURES: "approx,serde,rayon"
   RUSTFLAGS: "-D warnings"
-  MSRV: 1.64.0
-  BLAS_MSRV: 1.71.0
+  MSRV: 1.87.0
 
 jobs:
   latest_deps_stable: