build(nix): fix osmosis fetch via http (#252)

* update cosmos.nix branch

* update osmosis lock

* prefetch the git source

* rm osmosis pre-fetch step

* revert cosmos.nix pr branch

* update cosmos.nix lock

* update nixpkg and rust-overlay lock

.github/workflows/hermes.yaml

@@ -36,18 +36,6 @@ jobs:
             relayer -> relayer/target
             light-client -> light-client/target
 
-      - name: Pre-fetch Osmosis repo
-        run: |
-          OSMOSIS_REV=`nix flake metadata --json | jq -r '.locks.nodes["osmosis-src"].locked.rev'`
-          for i in `seq 1 10`; do
-            if nix flake prefetch "github:osmosis-labs/osmosis/${OSMOSIS_REV}"; then
-              exit 0
-            else
-              sleep 2
-            fi
-          done
-          exit 1
-
       - name: Nix build
         env:
           RUST_BACKTRACE: 1