chore(nix->guix): delete Nix estate-wide (#138) (#43)

Automated sweep to eradicate Nix from the estate as Guix is now the sole
reproducible environment.

Author: hyperpolymath

.github/workflows/governance.yml

@@ -13,4 +13,4 @@ permissions:
 
 jobs:
   governance:
-    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@81dbf2dd854b1444fd6236fa2352474383b2c2b9
+    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@81dbf2dd854b1444fd6236fa2352474383b2c2b9

.github/workflows/hypatia-scan.yml

@@ -16,4 +16,4 @@ permissions:
 
 jobs:
   scan:
-    uses: hyperpolymath/standards/.github/workflows/hypatia-scan-reusable.yml@81dbf2dd854b1444fd6236fa2352474383b2c2b9
+    uses: hyperpolymath/standards/.github/workflows/hypatia-scan-reusable.yml@81dbf2dd854b1444fd6236fa2352474383b2c2b9