ci: Upgrade golang to 1.20

Author: oxyno-zeta

.github/workflows/ci.yml

@@ -39,7 +39,7 @@ jobs:
       - uses: actions/checkout@3df4ab11eba7bda6032a0b82a6bb43b11571feac # v4
       - uses: actions/setup-go@v4
         with:
-          go-version: "^1.17.0"
+          go-version: "^1.20.0"
       - run: make test/unit
       - run: make test/coverage
       - run: go install github.com/mattn/goveralls@latest