docs: Update Spring note in README

[saig0]

Description

Update the note about the Spring integration in the README.

Update the announcement about Camunda Process Test.

Related issues

[github-actions]

Test Results

 3 files   -  46   3 suites   - 46   0s ⏱️ - 1m 33s
12 tests  - 126  11 ✅  - 127  0 💤 ±0  1 ❌ +1 
 3 runs   - 432   0 ✅  - 435  0 💤 ±0  3 ❌ +3 

For more details on these failures, see this check.

Results for commit 6cc2d7a. ± Comparison against base commit bdaa836.

This pull request removes 126 tests.

io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatActivatedJobReturnsJobAssert
io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatDeploymentEventReturnsDeploymentAssert
io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatInspectedProcessInstanceReturnsProcessInstanceAssert
io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatProcessInstanceEventReturnsProcessInstanceAssert
io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatProcessInstanceResultReturnsProcessInstanceAssert
io.camunda.zeebe.process.test.assertions.BpmnAssertTest ‑ testAssertThatPublishMessageResponseReturnsMessageAssert
io.camunda.zeebe.process.test.assertions.VariablesMapAssertTest$ContainsVariable ‑ shouldNotThrowAssertionErrorWhenVariableIsKnown
io.camunda.zeebe.process.test.assertions.VariablesMapAssertTest$ContainsVariable ‑ shouldThrowAssertionErrorWhenVariableIsUnknown
io.camunda.zeebe.process.test.assertions.VariablesMapAssertTest$HasVariableWithValue ‑ shouldBeLenientWithRespectToFieldOrder
io.camunda.zeebe.process.test.assertions.VariablesMapAssertTest$HasVariableWithValue ‑ shouldNotThrowAssertionErrorWhenVariableIsKnownAndValueIsCorrect
…

♻️ This comment has been updated with latest results.

[akeller]

See more context here.