Build Nix package on GitHub actions

.github/workflows/main.yml

@@ -10,13 +10,23 @@ on:
   #   - cron: '0 0 * * 0'
 
 jobs:
+  nix-build:
+    name: Nix build
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v5
+    - uses: DeterminateSystems/determinate-nix-action@v3
+    - name: build flake
+      run: |
+        nix build .#
+
   build:
     name: GHC ${{ matrix.ghc-version }} on ${{ matrix.os }} / build
     runs-on: ubuntu-latest
     strategy:
       matrix:
         os: [ubuntu-latest]
-        ghc-version: ['9.10', '9.8', '9.4']
+        ghc-version: ['9.10', '9.8', '9.6']
 
         include:
           - os: windows-latest
@@ -25,7 +35,7 @@ jobs:
             ghc-version: '9.8'
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v5
 
     - name: Set up GHC ${{ matrix.ghc-version }}
       id: setup

fints2ledger.cabal

@@ -82,7 +82,7 @@ library fints2ledger-lib
     , filepath >=1.4.2 && <1.6
     , generic-lens >=2.2.2 && <2.3
     , haskeline >=0.8.2 && <0.9
-    , hledger-lib >=1.27.1 && <1.43
+    , hledger-lib >=1.27.1 && <1.51
     , lens >=5.1.1 && <5.4
     , optparse-applicative >=0.17.1 && <0.19
     , regex-tdfa >=1.3.2 && <1.4
@@ -144,7 +144,7 @@ test-suite fints2ledger-test
     , base
     , containers
     , fints2ledger-lib
-    , sydtest >= 0.15 && <= 0.20
+    , sydtest >= 0.15 && <= 0.23
     , transformers
     , text
     , time