OSCAL 1.0.0-rc2 annotation changed to prop

[GaryGapinski]

This PR changes all occurrences of <annotation> to <prop> in the Schematron, XSpec, FedRAMP extensions, and FedRAMP value constraints.

The XSpec unit tests had no failures.

Applying validate_with_schematron.sh to src/templates/ssp/xml/FedRAMP-SSP-OSCAL-Template.xml shows 22 differences. Results (master branch vs 1.0.0-rc2) in
svrl.zip.

By the way, the several FedRAMP-SSP-OSCAL-Template.xml differ in version:

./oscal/src/release/content-upgrade/FedRAMP-SSP-OSCAL-Template.xml
      <oscal-version>1.0-Milestone3</oscal-version>
            <oscal-version>1.0-Milestone3</oscal-version>
            <oscal-version>1.0-Milestone3</oscal-version>
./src/templates/ssp/xml/FedRAMP-SSP-OSCAL-Template.xml
      <oscal-version>1.0.0-rc2</oscal-version>
            <oscal-version>1.0.0-rc2</oscal-version>
./resources/validations/test/demo/FedRAMP-SSP-OSCAL-Template.xml
      <oscal-version>1.0-Milestone3</oscal-version>
            <oscal-version>1.0-Milestone3</oscal-version>
            <oscal-version>1.0-Milestone3</oscal-version>
./templates/ssp/xml/FedRAMP-SSP-OSCAL-Template.xml
      <oscal-version>1.0.0-rc2</oscal-version>
            <oscal-version>1.0.0-rc2</oscal-version>

[danielnaab]

Looks good to me, I just found a few "a / an" issues from the rename.

[github-actions]

XSpec Test Results

  1 files  ±0    2 suites  ±0   0s ⏱️ ±0s
43 tests ±0  43 ✔️ ±0  0 💤 ±0  0 ❌ ±0 

Results for commit e43427c. ± Comparison against base commit e43427c.