mgmt compute update readme.java.md (#12753)

specification/compute/resource-manager/readme.java.md

@@ -16,6 +16,7 @@ output-folder: $(azure-libraries-for-java-folder)/azure-mgmt-compute
 
 ```yaml $(java) && $(multiapi)
 batch:
+  - tag: package-2020-10-01-preview
   - tag: package-2020-06-01
   - tag: package-2019-07  
   - tag: package-disks-2018-04
@@ -24,6 +25,19 @@ batch:
   - tag: package-compute-2017-03
 ```
 
+### Tag: package-2020-10-01-preview and java
+
+These settings apply only when `--tag=package-2020-10-01-preview --java` is specified on the command line.
+Please also specify `--azure-libraries-for-java-folder=<path to the root directory of your azure-sdk-for-java clone>`.
+
+``` yaml $(tag) == 'package-2020-10-01-preview' && $(java) && $(multiapi)
+java:
+  namespace: com.microsoft.azure.management.compute.v2020_10_01_preview
+  output-folder: $(azure-libraries-for-java-folder)/sdk/compute/mgmt-v2020_10_01_preview
+regenerate-manager: true
+generate-interface: true
+```
+
 ### Tag: package-2020-06-01 and java
 
 These settings apply only when `--tag=package-2020-06-01 --java` is specified on the command line.