go.mod,.github: upgrade to Go 1.21

There's an effort underway to upgrade to Go 1.21 before shipping 23.2. Begin
testing 1.21 in Pebble CI, and declare Go 1.21 in the go.mod file.

Informs cockroachdb/cockroach#97260.

.github/workflows/ci.yaml

@@ -21,7 +21,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: make test generate
 
@@ -34,7 +34,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v4
         with:
-          go-version: "1.20"
+          go-version: "1.21"
 
       - run: GOARCH=386 make test
 
@@ -47,7 +47,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: make crossversion-meta
 
@@ -60,7 +60,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: make testrace TAGS=
 
@@ -73,7 +73,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: make test TAGS=
 
@@ -86,7 +86,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: CGO_ENABLED=0 make test TAGS=
 
@@ -99,7 +99,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: make test
 
@@ -112,7 +112,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - run: go test -v ./...
 
@@ -125,7 +125,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - name: FreeBSD build
       env:
@@ -151,7 +151,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v4
       with:
-        go-version: "1.20"
+        go-version: "1.21"
 
     - name: mod-tidy-check
       run: make mod-tidy-check

.github/workflows/code-cover-gen.yaml

@@ -29,7 +29,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v2
         with:
-          go-version: "1.20"
+          go-version: "1.21"
 
       - name: Get list of changed packages
         shell: bash

.github/workflows/nightly-code-cover.yaml

@@ -24,7 +24,7 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v2
         with:
-          go-version: "1.20"
+          go-version: "1.21"
 
       - name: Generate coverage
         run: scripts/code-coverage.sh

.github/workflows/sanitizers.yaml

@@ -14,7 +14,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v2
       with:
-        go-version: "1.20.1"
+        go-version: "1.21"
 
     - run: make testasan
 
@@ -27,6 +27,6 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v2
       with:
-        go-version: "1.20.1"
+        go-version: "1.21"
 
     - run: make testmsan

go.mod

@@ -43,4 +43,4 @@ require (
 	gopkg.in/yaml.v3 v3.0.0 // indirect
 )
 
-go 1.20
+go 1.21