Integration test slowness workaround (#1413)

* Try installing 2.20.5 to see how performance is.

* Try installing with cachix again.

* Set build-users group.

* Delete custom script, cleanup workflow files.

* Fix shell-check lint.

.github/workflows/bench.yml

@@ -32,14 +32,10 @@ jobs:
         sed 's/nixbld:x:\([[:digit:]]*\):$/nixbld:x:\1:nixbld-1,nixbld-2,nixbld-3/' /etc/group > group-changed
         mv group-changed /etc/group
 
-    - name: run our custom nix install script
-      run : ./.github/scripts/install-nix.sh
-      shell: bash
-      env:
-        INPUT_NIX_PATH: "nixpkgs=channel:nixos-unstable"
-        INPUT_EXTRA_NIX_CONFIG: "build-users-group = nixbld"
-        INPUT_INSTALL_URL: ""
-        INPUT_INSTALL_OPTIONS: ""
+    - uses: cachix/install-nix-action@v25
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+        extra_nix_config: "build-users-group = nixbld"
 
     - name: Debugging information
       run: |

.github/workflows/integrations-test.yml

@@ -41,14 +41,10 @@ jobs:
         sed 's/nixbld:x:\([[:digit:]]*\):$/nixbld:x:\1:nixbld-1,nixbld-2,nixbld-3/' /etc/group > group-changed
         mv group-changed /etc/group
 
-    - name: run our custom nix install script
-      run : ./.github/scripts/install-nix.sh
-      shell: bash
-      env:
-        INPUT_NIX_PATH: "nixpkgs=channel:nixos-unstable"
-        INPUT_EXTRA_NIX_CONFIG: "build-users-group = nixbld"
-        INPUT_INSTALL_URL: ""
-        INPUT_INSTALL_OPTIONS: ""
+    - uses: cachix/install-nix-action@v25
+      with:
+        nix_path: nixpkgs=channel:nixos-unstable
+        extra_nix_config: "build-users-group = nixbld"
 
     - name: Debugging information
       run: |

.github/workflows/lint.yml

@@ -94,4 +94,4 @@ jobs:
         uses: sudo-bot/action-shellcheck@latest
         with:
             # https://github.com/koalaman/shellcheck#how-to-use
-            cli-args: "*.sh ./.github/scripts/*.sh"
+            cli-args: "*.sh"