Remove backward direction for ABI tests

Versions of the extension cannot be expected to always work in the
backwards direction so we cannot reliably test that builds against
later versions of PostgreSQL (e.g., 17.3) work with earlier versions
(e.g., 17.0) if new functions are introduced in the later version.

.github/workflows/abi.yaml

@@ -44,43 +44,18 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        dir: [ "forward", "backward" ]
         pg: [ 14, 15, 16, 17 ]
         include:
-          - dir: backward
-            pg: 14
-            builder: ${{ fromJson(needs.config.outputs.pg14_latest) }}-alpine3.19
-            tester: ${{ fromJson(needs.config.outputs.pg14_abi_min) }}-alpine
-            ignores: memoize
-          - dir: forward
-            pg: 14
+          - pg: 14
             builder: ${{ fromJson(needs.config.outputs.pg14_abi_min) }}-alpine
             tester: ${{ fromJson(needs.config.outputs.pg14_latest) }}-alpine3.19
-          - dir: backward
-            pg: 15
-            builder: ${{ fromJson(needs.config.outputs.pg15_latest) }}-alpine3.19
-            tester: ${{ fromJson(needs.config.outputs.pg15_abi_min) }}-alpine
-          - dir: forward
-            pg: 15
+          - pg: 15
             builder: ${{ fromJson(needs.config.outputs.pg15_abi_min) }}-alpine
             tester: ${{ fromJson(needs.config.outputs.pg15_latest) }}-alpine3.19
-          - dir: backward
-            pg: 16
-            builder: ${{ fromJson(needs.config.outputs.pg16_latest) }}-alpine3.19
-            tester: ${{ fromJson(needs.config.outputs.pg16_abi_min) }}-alpine
-            # this test has issues with 16.0 version of pg_dump binary
-            # which affects backwards test only 
-            ignores: pg_dump_unprivileged
-          - dir: forward
-            pg: 16
+          - pg: 16
             builder: ${{ fromJson(needs.config.outputs.pg16_abi_min) }}-alpine
             tester: ${{ fromJson(needs.config.outputs.pg16_latest) }}-alpine3.19
-          - dir: backward
-            pg: 17
-            builder: ${{ fromJson(needs.config.outputs.pg17_latest) }}-alpine3.19
-            tester: ${{ fromJson(needs.config.outputs.pg17_abi_min) }}-alpine
-          - dir: forward
-            pg: 17
+          - pg: 17
             builder: ${{ fromJson(needs.config.outputs.pg17_abi_min) }}-alpine
             tester: ${{ fromJson(needs.config.outputs.pg17_latest) }}-alpine3.19
 
@@ -89,7 +64,7 @@ jobs:
     - name: Checkout TimescaleDB
       uses: actions/checkout@v4
 
-    - name: Build extension
+    - name: Build extension with ${{ matrix.builder }}
       run: |
         BUILDER_IMAGE="postgres:${{matrix.builder}}"
 
@@ -113,7 +88,7 @@ jobs:
           cp `pg_config --pkglibdir`/timescaledb*.so build_abi/install_lib
         EOF
 
-    - name: Run tests
+    - name: Run tests on server ${{ matrix.tester }}
       run: |
         TEST_IMAGE="postgres:${{ matrix.tester }}"