chore(deps): upgrade gapic-generator-java to 2.8.0 and update gax-jav…

…a to 2.18.1 (googleapis#683)

- [ ] Regenerate this pull request now.

PiperOrigin-RevId: 450543911

Source-Link: googleapis/googleapis@5528344

Source-Link: https://github.com/googleapis/googleapis-gen/commit/9f6775cab1958982b88967a43e5e806af0f135db
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiOWY2Nzc1Y2FiMTk1ODk4MmI4ODk2N2E0M2U1ZTgwNmFmMGYxMzVkYiJ9

java-os-login/google-cloud-os-login/src/main/java/com/google/cloud/oslogin/v1/OsLoginServiceClient.java

@@ -16,7 +16,6 @@
 
 package com.google.cloud.oslogin.v1;
 
-import com.google.api.core.BetaApi;
 import com.google.api.gax.core.BackgroundResource;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.oslogin.common.OsLoginProto;
@@ -120,7 +119,6 @@ public static final OsLoginServiceClient create(OsLoginServiceSettings settings)
    * Constructs an instance of OsLoginServiceClient, using the given stub for making calls. This is
    * for advanced usage - prefer using create(OsLoginServiceSettings).
    */
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public static final OsLoginServiceClient create(OsLoginServiceStub stub) {
     return new OsLoginServiceClient(stub);
   }
@@ -135,7 +133,6 @@ protected OsLoginServiceClient(OsLoginServiceSettings settings) throws IOExcepti
     this.stub = ((OsLoginServiceStubSettings) settings.getStubSettings()).createStub();
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   protected OsLoginServiceClient(OsLoginServiceStub stub) {
     this.settings = null;
     this.stub = stub;
@@ -145,7 +142,6 @@ public final OsLoginServiceSettings getSettings() {
     return settings;
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public OsLoginServiceStub getStub() {
     return stub;
   }

java-os-login/google-cloud-os-login/src/main/java/com/google/cloud/oslogin/v1/stub/OsLoginServiceStubSettings.java

@@ -136,7 +136,6 @@ public UnaryCallSettings<GetLoginProfileRequest, LoginProfile> getLoginProfileSe
     return updateSshPublicKeySettings;
   }
 
-  @BetaApi("A restructuring of stub classes is planned, so this may break in the future")
   public OsLoginServiceStub createStub() throws IOException {
     if (getTransportChannelProvider()
         .getTransportName()