Reduce x/crypto and x/sys versions to match Go 1.21

CIRCL does not necessarily depend on newer x/crypto and x/sys versions.
Lower the version requirements to match Go 1.21.7, this avoids the need
to upgrade stdlib dependencies when integrating circl.

For reference, we drop these `golang.org/x/crypto` commits:

    $ git -C ../golang-crypto log --oneline 2e82bdd1719d..v0.17.0 $(go list -deps ./... | grep golang.org/x/crypto/ | sed 's,golang.org/x/crypto/,./,')
    $ git -C ../golang-crypto log --oneline 2e82bdd1719d..v0.17.0 ./blake2b ./blake2s ./hkdf ./internal/alias ./chacha20 ./internal/poly1305 ./chacha20poly1305 ./cryptobyte/asn1 ./cryptobyte ./sha3
    b8ffc16 blake2b: drop Go 1.6, Go 1.8 compatibility
    bda2f3f argon2: avoid clobbering BP
    a2edfb5 cryptobyte: fix ReadOptionalASN1Boolean
    df0bc9e chacha20poly1305: guard PSHUFB usage with GOAMD64_v2
    74c2ba9 crypto/hkdf: remove useless call to Reset
    8779cbd all: update go directive to 1.18
    ec07f4e chacha20: drop Go 1.10 compatibility for arm64
    3f0842a sha3: have ShakeHash extend hash.Hash
    e90f1e1 cryptobyte: add uint48 methods

No commits are dropped for `golang.org/x/sys/cpu`.

go.mod

@@ -4,6 +4,6 @@ go 1.21
 
 require (
 	github.com/bwesterb/go-ristretto v1.2.3
-	golang.org/x/crypto v0.17.0
-	golang.org/x/sys v0.15.0
+	golang.org/x/crypto v0.11.1-0.20230711161743-2e82bdd1719d
+	golang.org/x/sys v0.10.0
 )

go.sum

@@ -1,6 +1,6 @@
 github.com/bwesterb/go-ristretto v1.2.3 h1:1w53tCkGhCQ5djbat3+MH0BAQ5Kfgbt56UZQ/JMzngw=
 github.com/bwesterb/go-ristretto v1.2.3/go.mod h1:fUIoIZaG73pV5biE2Blr2xEzDoMj7NFEuV9ekS419A0=
-golang.org/x/crypto v0.17.0 h1:r8bRNjWL3GshPW3gkd+RpvzWrZAwPS49OmTGZ/uhM4k=
-golang.org/x/crypto v0.17.0/go.mod h1:gCAAfMLgwOJRpTjQ2zCCt2OcSfYMTeZVSRtQlPC7Nq4=
-golang.org/x/sys v0.15.0 h1:h48lPFYpsTvQJZF4EKyI4aLHaev3CxivZmv7yZig9pc=
-golang.org/x/sys v0.15.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/crypto v0.11.1-0.20230711161743-2e82bdd1719d h1:LiA25/KWKuXfIq5pMIBq1s5hz3HQxhJJSu/SUGlD+SM=
+golang.org/x/crypto v0.11.1-0.20230711161743-2e82bdd1719d/go.mod h1:xgJhtzW8F9jGdVFWZESrid1U1bjeNy4zgy5cRr/CIio=
+golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
+golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=