Update GHA checkout node & R version

- updated 'checkout' action to v4, as a node used by the previous
  version (v3) is now deprecated
- specified R version to use on MacOS and Windows, to match SomaLogic's development
  and maintenance environment

.github/workflows/check-standard.yaml

@@ -36,9 +36,8 @@ jobs:
       fail-fast: false
       matrix:
         config:
-          - {os: macos-latest, r: 'release'}
-          - {os: windows-latest, r: 'release'}
-          #- {os: ubuntu-latest, r: 'release'}  # was taking too long to build
+          - {os: macos-12, r: '4.3.2'}
+          - {os: windows-latest, r: '4.3.2'}
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
@@ -47,7 +46,7 @@ jobs:
       TZ: 'America/Denver'
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-pandoc@v2
 

.github/workflows/test-coverage.yaml

@@ -23,16 +23,17 @@ name: test-coverage
 
 jobs:
   test-coverage:
-    runs-on: macOS-12
+    runs-on: macos-12
 
     env:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - uses: r-lib/actions/setup-r@v2
         with:
+          r-version: '4.3.2'
           use-public-rspm: true
 
       - uses: r-lib/actions/setup-r-dependencies@v2
@@ -51,7 +52,7 @@ jobs:
 
       #- name: Upload results to Codecov 🚀
       #  uses: codecov/codecov-action@v3.1.2
-      
+
       - name: Show 'testthat' output
         if: always()
         run: |