Prometheus shouldn't be rebuilt everytime we rebuild the program even if there's no change at all.

[XuanYang-cn]

Please state you issue using the following template and, most importantly, in English.
Everytime when I rebuilt, prometheus will be rebuilt, even if there's no change at all. This is not a good feature.

Describe the bug
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Steps/Code to reproduce behavior
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Expected behavior

When we rebuild a built project:

1. Thirdparty libs shouldn't be rebuilt
2. Only altered libs should be rebuilt

Environment details

• Hardware/Softward conditions (OS, CPU, GPU, Memory)
• Method of installation (Docker, or from source)
• Milvus version (v0.3.1, or v0.4.0)
• Milvus configuration (Settings you made in server_config.yaml)

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Additional context
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