Run benchmarks using Julia v1.11

Also, delete manifest now that we can point to the right `ParticleDA` using the
`[sources]` section of the project file.  This should make it easier to run
benchmarks when updating list of dependencies of `ParticleDA`.

Author: giordano

.github/workflows/benchmark.yml

@@ -24,7 +24,7 @@ jobs:
       - uses: actions/checkout@v5
       - uses: julia-actions/setup-julia@v2
         with:
-          version: '1.10.2'
+          version: '1.11'
       - uses: julia-actions/cache@v2
         with:
           cache-name: "benchmarks"

.gitignore

@@ -1,5 +1,6 @@
 .DS_Store
 Manifest.toml
+Manifest-v*.toml
 /dev/
 /docs/build/
 /.benchmarkci