Fix remaining lint issues incl. ignore io/ioutil deprecation warnings

io/ioutil touches a large amount of the codebase so is a not-insignificant change to remedy. For now ignore these lint errors as ioutil now only operates as a simple delegate for the preferred os and io packages anyway.
If we want to correctly resolve these lint issues, upstream PR ethereum/go-ethereum#24869 can provide guidance.

.golangci.yml

@@ -68,3 +68,6 @@ issues:
     - 'SA1019: strings.Title is deprecated'
     - 'SA1019: strings.Title has been deprecated since Go 1.18 and an alternative has been available since Go 1.0: The rule Title uses for word boundaries does not handle Unicode punctuation properly. Use golang.org/x/text/cases instead.'
     - 'SA1029: should not use built-in type string as key for value'
+    # quorum: ignore due to large number of changes required to remedy. ioutil now only operates as a simple delegate for the preferred os and io packages anyway.
+    #   If we want to correctly resolve these lint issues, upstream PR https://github.com/ethereum/go-ethereum/pull/24869 can provide guidance.
+    - 'SA1019: "io/ioutil" has been deprecated since Go 1.19: As of Go 1.16, the same functionality is now provided by package .io. or package .os., and those implementations should be preferred in new code. See the specific function documentation for details.'

plugin/security/gateway.go

@@ -62,7 +62,6 @@ func transform(tlsData *proto.TLSConfiguration_Data) (*tls.Config, error) {
 		cipherSuites = defaultCipherSuites
 	}
 	tlsConfig.CipherSuites = cipherSuites
-	tlsConfig.PreferServerCipherSuites = true
 
 	cer, err := tls.X509KeyPair(tlsData.GetCertPem(), tlsData.GetKeyPem())
 	if err != nil {

plugin/security/gateway_test.go

@@ -51,7 +51,6 @@ func TestTransform_whenTypical(t *testing.T) {
 	cfg, err := transform(abitraryTLSConfigurationData)
 
 	assert.NoError(err)
-	assert.True(cfg.PreferServerCipherSuites)
 	assert.EqualValues(defaultCipherSuites, cfg.CipherSuites)
 	assert.Equal(uint16(tls.VersionTLS12), cfg.MinVersion)
 	assert.EqualValues([]tls.CurveID{